Well, the leak came from THREE diffrent people, and had some newcomers/psuedo newcomer (not in Brawl but in Melee and returning (*cue ROY or MEWTWO*), namely Shulk (DUH. He's more than likely going to be in the game.), Duck Hunt Dog (WTF), Doctor Mario (Psuedo newcomer), and Bowser Jr. (I would play as him if he's in the game. Once) One of the leaks also had a team battle with Lucina and Shulk (Red Team) vs Charizard and FAWKING GANONDORF (Blue Team). Red Team won, and there is victory poses and clapping (Lucina /MAY/ have the same as Marth, just Englished, or completley diffrent.) The name for one of the players in leak one (with Character select/stage select) was: ERSB0083, ERSB rating games for NA. For stages, there wasn't much, though the leaker did say that Guar Plains on Bionis Knee was a stage. And what did I see in the corner? What looked like Guar Plains. So yeah.
If this is true Duck Hunt Dog and more importantly Shulk will be my mains. NO BUTS ABOUT IT. Them.

^Whoops forgot Dark Pit