In all honesty, I think the Wii Fit trainer will be a waste of space... But, here's what I would want for this game!
Tatanga
King K. Rool
Pico
Waluigi
Birdo
Krystal
Paper Mario
Captain Syrup
Rudy The Clown
A good Wario, please?
Pac-Man (I know he's from Namco, but if they can use Capcom's mascot, why not Namco's, as well?)
Black Shadow
Eggplant Man
Geno
Zant