That's quite a good question actually, even though it can never be confirmed until the game comes out.... if there IS a game.
There was Donald and Goofy... and in a way, watching Disney, you get the feeling that Donald and Goofy are just two main characters; usually in the situation of having to have Disney party members, Donald and Goofy are the first choice, however, now that they're out of the way, it's hard to guess who they would choose as the next set of party members..... all we can really do is wait :/