So if we are talking about those who should advance from this round to the next one, then these two should be:
1. Boa Hancock (the obvious choice. I believe she might take both Apoo and Inazuma at the same time. Of course she might have some problems, but I doubt as Apoo's attacks seem quite long to perform if they are more or less strong and Inazuma even if he is somewhere around pre-timeskip Luffy he is still not strong enough to take Boa Down, especially since she is Master of Haki and her DF is quite broken)
2. Inazuma. He seems one of the strongest guys in Revolutionary Army and seems to be just under the commanders (like Ivankov and some others who are going to be shown in the future). Before timeskip he was shown to seemingly be around Luffy, but more experienced. He was in the 5th Level of Impel Down, so obviously he should be quite a strong guy and obviously stronger than Apoo as the guy was conciderably weaker than Luffy before timeskip and even if he managed to perform several strong attacvks they require long preparations, so Inazuma would win as he seems overall better fighter. And the same Apoo didn't show anything apart from his DF.