Just my two cents, but what if the Movie, for once in this crazy world of ours, actually doesn't take place chronologically as the anime occurs. I know it screws it up, but it would explain Charizard possibly remaining and Oshawott being there. That being the case, maybe Oshawott evolves fighting the scalchop king Dewott and then it could decide to stay or go. I know we're all riled up about this, but I would perfectly ok with the movie being a little out of place because it just seems like it will be a great movie, the first one i'll really want to see in a while. I'm willing to put up with it if it means an evolved Oshawott or even it leaving because it would be SOMETHING for Oshawott's development besides being a piece of merchandise on Ash's belt. I would love Charizard to stay, and maybe he will. We don't know much right now regardless, so let's be willing to dream a little a bit.