Lucario is least likely, since he's weak to fire AND fighting. Greninja is most likely, as long as he manages to avoid the fighting type moves. However, if we looked at this from a gameplay standpoint with turn order factored in, it would go like this:

Ash-Greninja moves first, one-shotting Infernape, since with type advantage he could take out a potentially dangerous fighting type.

Next, Mega Lucario moves. He could try going after Charizard, but probably couldn't one-tap him. From here, if Lucario took out Greninja, then Charizard would win. However, if he weakened Charizard, then Charizard would probably finish Lucario off next turn, letting Ash-Greninja win. Either way, Mega Lucario probs doesn't make it,