Without any relation to that sucky game Smash Bros. X, the game features up to 40-50+ characters. Now, I know I do have evidence, and I will be soon working on it. See my avatar, that is one piece of evidence. I do have some confirmed characters.

Veteran:
Link
Mario
Kirby
Meta Knight
Sonic
Fox
Captain Falcon
Pikachu
Mewtwo
Ness

Newcomer:
Bomberman
Goku
Mega Man
Ristar
Mach Rider
Krystal
Vaati
Melee Link

Unlockable:
Purin
Mr. Game and Watch
Ichigo
Naruto
Cloud
Axel

I also have some other confirmed stuff.

Items:
Assist Trophy
Wild Cards
Pokeballs
Star Man
Warp Star
Beam Sword

Modes:
Brawl X
Brawl
Special Brawl X
Special Brawl
Classic
Adventure
Adventure: Ascent of Shadows
Multi-man Brawl
Boss Battles

Difficulties:
V.V. Easy
V. Easy
Easy
Normal
Hard
V. Hard
Intense
Insane
V. Insane
X Smash

Updates soon.

That roster is too random.
and revealing your roster was probably not your best decision.