I don't see the point. It's like you wanna totally plan out a game that will never get made, and if it ever were made, Square would do their own thing.
Bahh! Die nay sayers! It seems pretty fun to me...
Well since Square and Enix have come together than it would mean they could have characters from different Enix games as well. But I think it would be a good idea just to keep the Final Fantasy characters in there. Quistis would kick everyone's butt.