Characters:
Mario
Luigi
Peach
Bowser
Bowser Jr
Donkey Kong
Diddy Kong
King K. Rool
Yoshi
Little Mac
Link (Skyward Sword Art Style)
Zelda/Sheik (Skyward Sword Art Style)
Ganondorf (Skyward Sword Art Style)
Toon Link and Phantom Zelda (Ice Climber Style)
Ghirahim
Samus/Zero Suit Samus
Ridely
Anthony Higgs
Pit
Magnus
Kirby
Meta Knight
King Dedede
Wario
Captain Syrup
Fox
Falco
Krystal
Wolf
R.O.B
Pikachu
Jigglypuff
Pokemon Trainer(3DS let you customize all starters usages)
Mewtwo
Lucario
Captain Falcon
Samurai Goroh
Ness
Lucas
Zoroark
Marth
Ike
Lyndis
Chrom
Captain Olimar
Mr. Game n Watch
Ice Climber
Project P-100 Heroes
Andy
Isaac
Isa
Starfy
Jill Dozer
Shulk
Zael
Sonic
Megaman X
Pac-Man
Snake
Cecil Paladin/Dark Knight like Zelda and Sheik
Total Characters: 60
Wii Disc is 12 GB and SSBB takes about 6GB of it.
Wii U Disc is 25 GB and I expect SSB Wii U to take at least
16GB at minimum.