Well, remove 3 (Sonic, Pacman and Megaman), and you've got 35 characters. Melee's starting line up had 15 characters, that's bigger than the original's final line up (12). Brawl's starting line up had 25 characters, that's almost as big as Melee's full line up (26). I could see 1 or 2 other newcomers revealed before release, alongside 3 veterans, adding up to around 39 in total, with the remaining being unlockable characters - only the third party ones revealed before release like done with Brawl.
The one oddity is the entire FE line up being there from the start, but I don't think it'd be without precedent. Kirby had three characters in Brawl, with two newcomers, and they were all starters.