I don't see an egghead thread here so now, given the new developments.
Yamato - father gone
Vivi - father gone, unsafe in Alabasta unbeknownst to her
Bonney - Said she lost her crew and we don't know the Kuma situation
Hancock - Unsafe Amazon Lily
Well from what has came post Wano.
Vivi is D clan, Bonney is half celestial Dragon, Yamato is a different species and Hancock is a Celestial Dragon slave.
Yamato would fit being a different species. Although not to the same extent, Luffy has some Big Mom in him in terms of variety of crew. He has a talking reindeer and a skeleton and a cyborg (although that is not a species). Technically Luffy may turn out like all the Yonko, except Blackbeard and Kaido, as well as being like Roger.
Big Mom - Different species
Whitebeard - Protective of his crew
Shanks - Well balanced crew
Roger - Numerous Conqueror's
So alright Yamato some assume is gone from consideration and some presume it is a Jinbe situation. I feel like Yamato may actually set out to sea. Although it is hinted that Wano people have poor navigation skills and Yamato has not ever left the island. So that works against her. The whole idea of Yamato not leaving until after they return to Wano feels like it doesn't fit the whole waiting until Momonosuke becomes a great protector of Wano. I recall that Oden returned to Wano and left. And Oden leaving at that time was when Kaido had already invaded. It seems off that Yamato following in Oden's footsteps would remain in Wano and already be there for the invasion rather than being a strawhat and coming back to learn of the Wano situation. And it would be an opposition to how Greenbull invaded when Yamato and the Strawhats were already on the island, as well as Yamato being in the grouo first to make contact with Greenbull.
Bonney - Her story of being a half revolutionary child and half celestial dragon child, with a revolutionary/warlord etc., adoptive parent fits Luffy having characters of tragic background. Each of them had a form of tragedy except Jinbe. Technically it would be a bit of rehashing, Nami bellemere but yet Franky has a very similar story. She would have lost her parent and adoptive parent because of the Celestial Dragons. Which fits more of a revolutionary army member. And she may just well become that. But her ability makes for interesting fights.
Vivi - Well she is a D clan member. And lost her father. And technically would be in danger in her homeland. And is a Imu/Gorosei target. Her being under Luffy protection would make sense. But her being under revolutionary army protection fits as well. Since her nation is basically the one "original" nation that didn't follow the rest of the celestial dragons.And technically it was the next major arc after we came across Dragon. As a strawhat I guess she'd balance out the addition of Jinbe.
Hancock - First of all her Devil fruit is overpowered. So I don't know how Oda makes battles for someone like that. But here is something. Luffy beat Kaido. Kaido was worried about the invasion of Big Mom and technically is a Junior to Big Mom. Nami mentioned if they were going to battle a Yonko they'd need a full crew. We saw that Luffy still needed the help of numerous strong allies to defeat Kaido. It was mentioned that even if you take out the leader, you still have to handle the commanders. Basically hinting that just because Luffy unlocked Gear 5 doesn't mean he wins every situation, even if Gear 5 happened after this mention. Even so, Luffy needed Kidd (another conqueror) and Law (two awakened Devil Fruit users), Killer, Marco (Whitebeard's second in command), the defection of X Drake, Hyougoro (and his previous strength), Yamato (another Conqueror and Mythical Zoan) not aiding Kaido and helping Luffy, Big Mom momentarily switching sides. I won't include Marco getting rid of the Big Mom pirates. As the addition of Big Mom alone did greatly increase the difficulty.
Even so, the help Luffy got was basically levels greater than any help Luffy has ever gotten in any other arc. Now Oda just showed how difficult it was to invade another Yonko territory even without half of Blackbeard's crew and Blackbeard present. Oda also showed Shanks by himself decimating Kidd who had just, with Law, held his own in battle with Big Mom (even though they were obviously way weaker and Luffy is way stronger). Oda even made sure to indicate Kidd was healed up. And the whole Shanks not seeing Luffy was basically another indication that Luffy isn't at a certain level yet. Then you consider an up and coming Blackbeard was still collecting Devil Fruits when he had just became a Yonko, would indicate Luffy's crew strength has a long way to go. Now to Hancock, while Hancock herself is overpowered with her Devil Fruit, she was shown basically overmatched by Blackbeard even if not by the other commanders. It is hard to find a way to draw up battles for her in my opinion. But I'm not the writer. One thing though even if not part of the actual storyline there was basically a time skip special regarding Hancock fighting alongside Luffy, may have been a hint of her sailing with Luffy in the future. Robin has a technically very overpowered Devil Fruit but Oda found a way to make that not as ridiculously effective. I think with Hancock it is much more difficult though. Then she has Conqueror's which would put her above Zoro and Sanji, even with Zoro having Conqueror's. As per the design of the character, she has the whole tragic being a celestial dragon slave thing which kind of connects her indirectly to Jinbe, and slightly indirectly to Nami but not really. Like the other two women (Robin and Nami) Luffy basically saved them from living horrid futures. And isn't it a bit odd that Luffy is aiming to be Pirate King. And Hancock is named Pirate Empress. Eventhough Big Mom is the Yonko and deemed to be stronger. Just the title may hint joining Luffy. Also, we don't know if Hancock can use Conqueror's Haki coating, which contradicts my stronger than Zoro thing but the even so the Devil fruit gives her the edge even if she somehow has weaker Haki than Zoro. And it is interesting that the main powerful people outside of Ivankov in the war time period who helped Luffy were either Warlords or ex-warlords. Jinbe, Crocodile, Hancock, Buggy (slightly) and Law. One joined, another allied, two joined up themselves. She was similar to Dragon in people knowing the connection to Luffy is dangerous but now Hancock has no title to lose, so it basically doesn't really matter at all. As I saw elsewhere (not on this forum), her joining cross guild would seem contradictory to her nature. And odd to join a group that would oppose Luffy. And if you look at Ginny and Kuma, and the whole haven't seen Kuma in a while thing well (even if it is one sided), it has some similarity to Hancock situation. In the haven't seen Luffy in a while thing. You could say Gloriosa and Rayleigh were on opposing sides and ended up linked to Hancock but that may just be Oda setting to flip things with Hancock and Luffy in the same crew. Especially how technically the Kuma, Ginny, Bonney story has some slight slight similarity to Hancock situation. They may be flipped stories that go together. In one case, Bonney is considered Luffy's rival and a child, Hancock is technically no longer in a situation where she'd be forced to be in opposition to Luffy and thus could actually fill the role of being on his side. And in Luffy's crisis it was Jinbe and Hancock who were specifically there for him. And she even indicated affinity for serving no one but Luffy. While it is romantic love based, it fits the nature of the rest of his actual crew (like Zoro and Sanji refusing to serve under Kaido). And now this whole thing of Gloriosa being a Rocks member and on God Valley, Hancock a Celestial Dragon slave, and her being the Empress of Amazon Lily which may related to Alabasta, Ivankov being a Revolutionary and Celestial Dragon slave on God Valley and having an island of all a certain type of people while hancock had and island of all women (while you can say an Island of Giants is all Giants, Ivankov and Hancock have islands that relate to a specific gender classification rather than species or role), there may be something to all of it. Since it appears the real enemy will be the Imu and the Gorosei, while Bonney would have a real gripe with them, so too does Hancock being that she was enslaved on their island. She just fits into the whole, liberated by fishman, fishman linked to Nika, Luffy being Nika. Then possibly something about Athena and Medusa. Athena being a goddess of war or something like that, the Gorosei being called warrior God. And Luffy fits in to the good guy in all this. I mean for Oda to continually go on about Hancock being infatuated with Luffy and betraying her allegiances for Luffy (Warlords, the no men rule), it would seem a bit strange for Oda to then make her a side character. Especially after having her mentioning wanting to go meet up with Luffy. Something even Vivi doesn't indicate. So technically there is both Yamato and Hancock (two Conqueror's) indicating wanting to meet/join up with Luffy. Oda is showing the ex-Warlords are forming allegiances or related to allegiances. Doflamingo asking to team up with Crocodile during the war. Kuma offering his assistance to Moriah. Jinbe and Crocodile allying with Luffy in Impel Down. The Warlords joining up against Whitebeard. Law and Blackbeard at Rocky Port. Law and Jinbe essentially helping Luffy in Wano. Blackbeard attempting to recruit Moriah. Mihawk and Crocodile. Mihawk Buggy and Crocodile. Now if you notice, Crocodile is a jailed Warlord with a Warlord who lost their title by way of Pacifista now under a Yonko who became so at the same time as Luffy. The jailed warlord planned the team up with non jailed warlord. The jailed warlord joined, Jinbe, joined first. The non jailed warlord Hancock joins second. Crocodile was basically a Shadow King and Mihawk a lone person in his Kingdom. Hancock was the official Queen of the Island and lived isolated like Mihawk. The two replaced Yonko each had a warlord working for them (Doflamingo and Jinbe). Doflamingo a former king, ex-celestial dragon, went down from Marie Geiose but maintains his Celestial Dragon status unbeknownst to everyone. Hancock, ex-celestial dragon slave retains her celestial dragon marking. Hidden from public knowledge. Doflamingo, on Marie Geiose, then left and back to Marie Geiose (by way of still having Celestial Dragon swat). Hancock not from Marie Geiose, sent up to Marie Geiose (as a slave), rescued and back down below Marie Geiose. Doflamingo defeated by Luffy and jailed. Hancock allied with Luffy and free. Doflamingo a Conqueror that worked under Kaido. Hancock being a Conqueror who joins Luffy. There are just some interesting connections amongst the Warlords in relation to Luffy. How Hancock relates to Luffy through Doflamingo is that she would be the anti-Doflamingo. And as some people mentioned (either on or off this forum) with Bonney, Luffy actual uses her real name. I mean Yamato is Yamabro but Oden and Whitebeard were brother too. Now back to Hancock, her demeanor fits Choppers original nature in a reverse way. Chopper apprehensive to Luffy and pirates. Hancock disdain towards men. Would relate to her eventually adjusting personality through sailing with Luffy. People say individuals have to have a role, and I guess there really isn't a role for her to have on the ship. But of course Oda could possibly work that through developing her character. Hancock also has connection to Jinbe and Nami. Jinbe's Sun Pirates mark is basically her slave mark redone. Nami's Arlong tattoo was redone as well. So it would go, Hancock slave tattoo, Sun Pirates mark, and Arlong (of the Sun Pirates) mark. Which would also be the reverse order of their joining. If you recall, and this goes for Yamato as well, technically no one predicted what Jinbe's role would be. Then Oda came up with Helmsman. It is not like Luffy or the crew decided a Helmsman was needed. As opposed to Luffy pre-time skip, where technically a role of each character was implied prior or you could look back once they joined and realized hints. So maybe with the New World, Oda's design is not adding members for some specific pre-hinted role. And devising the role for them later.
Technically Robin wasn't a specific hinted needed role. As it wasn't really known about the Poneglyphs. But then it was right there in her introduction, and Luffy claiming to search for the One Piece, it is learned you need to be able to read the Poneglyphs.
Also, her is another possible Hancock hint. One through Dragon and Ivankov. Recall Ivankov said Ivankov catches Dragon staring to a certain direction (Goa). You can basically derive, Ivankov and Dragon, Dragon looking away from Ivankov indicating lack of attraction. Hancock's attraction to Luffy, and Luffy's complete obliviousness. Ivankov being co-founding member of Dragon's original group thus basically the right hand. Luffy aiming for Pirate King, Hancock pirate empress. Dragon and Ivankov breaking future Warlord Kuma out of jail. Luffy and Hancock ultimately being responsible for breaking ex-Warlord Jinbe out of jail. Both jailed in rebellion against the current authority. One after a battle, the other prior to one. Then you have Ivankov being the right hand, ultimately jailed and then Sabotage becoming the number 2. You have Hancock presumed stronger than Zoro, essentially Hancock a Number 2 to Luffy in strength (if you relate Marco vs Big Mom to Hancock and Blackbeard, Marco is a first mate) but she would of course be at the least second to Zoro. Ivankov jailing, replaced by Sabo as Number 2, then Ivankov coming back and Ivankov headquarters being the new base. Hancock with Luffy during the strawhats sent to different islands, Luffy and Hancock parting ways, Luffy reuniting with his crew, Hancock having to leave her Kingdom (Baltigo destroyed and Dragon headquartering at Ivankov), and hinting seeking out Luffy. And the Hancock, Ivankov connection both Celestial Dragon slaves. Hancock, as Blackbeard stated, has a very powerful devil fruit. Ivankov was about to eat Kaido's very powerful devil fruit while Ivankov was a slave. The relation to Sanji, with Sanji being adverse to those of Ivankov's island. And Sanji's obvious adoration of those in Hancock's kingdom (though Sanji hasn't been there). There is also, Ivankov leaving her sister to set sail after being enslaved. And eventually coming back for her sister.
Hancock after being freed from enslavement, stayed with her sisters. And is now seeking to part from them. Ivankov was directly freed by someone of Jinbe's kind. Jinbe was freed indirectly by way of Hancock helping Luffy.
(Side note: Zoro and Hancock both being conqueror's. Amazon Lily a female warrior land.
Wano, Zoro's implied lineage, land of samurai's usually male warriors. Yamato being a female wanting to be a Samurai like Oden, connects the two lands along with the Lily name and Alabasta). Ivankov being Iva of Miracles, Hancock being a Gorgon presumed to curse you.
There is a lot of linkage in the story that can basically give credence to Hancock joining Luffy officially.
Technically of the 4, Yamato is the one who fits seamlessly with her only drawback of being stronger than Zoro and Sanji, which can easily be made temporary. Technically all 4 of them seem to be without a destination. Now 2 of the 4, would have a connection to Dragon as well. Bonney linked to Kuma and Ginny as Revolutionaries, Dragon basically being responsible for Bonney and Kuma's situations. Could lead to Bonney being a revolutionary, even her being saved by Sabo. Sabo attempting to save Vivi father and learning of Vivi being a D Clan member. Technically while it was indicated to tell Luffy, the D clan stuff would link even more to Dragon's purpose since their enemy is specifically the Celestial Dragons. So her joining Dragon is even plausible. If you think about it, Vivi's situation was being in the middle of a revolution in her Kingdom. Which fits more with Revolutionary stuff. Desert Kingdom, the mention of Dragon not having enough resources for Vegapunk. Vegapunk choosing Marines over Dragon. Alabasta not joining the rest of the Celestial Dragons. Also Vivi possibly relates to Coby. Both who took blows from Luffy. One becomes a marine, the other actually turns out to be a revolutionary. One training under Garp and the other under Dragon. The other two, Yamato and Hancock, technically have no duties anymore. One is just traveling Wano, and the other seems to be set on leaving her Kingdom.
(Side note out topic: Didn't Supernova Killer sacrifice himself to a Yonko services for his crew, yet Sanji doing this regarding Big Mom lowered him to people. And this is a Supernova Killer who fought Kaido, indicating that Sanji has qualities of a first mate even if not superior to Zoro. And while Killer is not a conqueror, it does mean that Sanji has some linearity with first mate status is, and the actual first mate does have Conqueror's technically. Might just be some, look back and realize there was some indication that Sanji is on par with Zoro)
