That's why I said "starting line up" - I meant the characters who aren't hidden. Melee's reveal only hid Zelda, out of the starting cast, and that's because everyone assumed that the Zelda scene in the trailer was just a reference to Sheik's background. So, they could show the intro movie without problems.
Brawl's reveal trailer had many starting characters left out though, with them only getting revealed months later through the Dojo or other events (IIRC, Fox was revealed before the Dojo opened, in a separate teaser. There was also Sonic). That's why I think we're going to get something closer to Brawl's reveal, rather than Melee's. I don't think they'll reveal the entire non-unlockable cast, aside from some alternate forms, right in the first trailer here. 4-5 Newcomers for the first trailer should be good enough anyway. Melee's starting cast had that number too.