People have been saying Peach for at least a month, they're just saying it out of desperation, if Zelda wasn't already confirmed, I'd be doing so too.Why is everyone expecting Peach? Peach will be later. Dont forget that time with Yoshi's Music and Stage coming out before him...
I say Falcon as a character.
Stage, most likely, Pokemon Stadium, since the pokemon are the only ppl with no stage
Music, Mario (music is hugely doubtable)
AT- Chef Kawalski
Pokeball: Dialga+Palkia