I see no point of arguing "YES Zodd is there" or "NO he isn't." We'll just have to wait and see....
Personally, I can sort of see the horn and wing suggested by Aldrich, and previous frames with Gutts sensing something could be explained by Zodd's shadow cameo. If the horn & wing are put there on purpose it's meant to VERY obscure, and I doubt Miura would explicitly explain what Guts sensed in that very moment. However, if IT IS Zodd, and he WAS bringing baby Guts(ka) to see his parents, then we have some even bigger questions -->
Is he also controlled by Griffith?
Is G part of him (Does G also exist within him)?
Is he a separate entity from G all together?
Hmmm... in proposing these questions, I may have come up with another theory....
So let's say the kid IS Gutska (I hate this name but it saves me time).... We saw the baby spirit being eaten by the Egg dude, and we saw him evolve into Griffith's new body. In other words, we KNOW for sure that Griffith used Gutska's would-be body and made it his own. We also saw how Gutska caused some stirring feelings with Griffith during the fight on the hill of swords, but Griffith claims that he has let go of his feelings for Guts/Caska/theGoldenDays. So it can be inferred that Gutska was solely responsible for those stirring feelings (perhaps of hesitation? fear?).
Considering this evidence, I was wondering if Gutska could be a hinderance to Griffith's plans, since he can't afford a single shread of hesitation in the excution of his ambition. Keep in mind that G is a vastly powerful being. He is almost never wrong about things about which he is sure, and apparently he was sure that he could remain cold towards the possibility of Zodd killing Guts, yet he could feel the physical effects of Gutska's thoughts. Perhaps Griffith recognized the potential for Gutska to develop into a larger hinderance, and tried to purge Gutska's existence from his own. I don't know if anyone here has read/seen Inuyasha, but I was thinking along the lines of how Naraku purges parts of himself to create lesser demons. In the same way, perhaps Griffith realizes that his new found existence includes the existence of Gutska, and his tangible body is not 100% his. Thus, he has separated Gutska's existence from his body by purging the existence of Gutska (a pure form of Gutska) from himself, and creating a pseudo off-spring viz. the kid on the beach.
There are some problems with this theory.
1) If Griffith was so powerful, why doesn't he just eliminate Gutska all together?
2) Why would Gutska have a physical body?
3) If this is so, and supposing that Zodd really was at that beach, why would Zodd help the kid?
4) Considering the evidence that I proposed in the 2nd page, why would Gutska have such a saintly spiritual form (the elemental-like spirit form)?
I hope I'm not running a muck here. That was very long, but do you guys understand the gist of my theory? Comments please...