I'm going to throw my weight behind the theory that we will be getting 2 more pre-ballot characters and 4 ballot ones, the two "marios" in the game's code to be filled with the pre-ballot ones.
Pre-Ballot:
Wolf
Veteran/Cut Character - Either Pichu, Chorus Men, etc.
Ballot:
King K. Rool
Isaac
Bandana Dee
Krystal or Shantae
That's my theory and I'm sticking to it. And it's a damn impressive roster I believe.
Edit: To be fair, Isaac is definitely popular in the US, almost K Rool levels as such. The thing is, from what I've seen and what I've heard, Isaac has no such popularity in Japan and I think that's a big kicker. BDee might not have as much US support as Isaac but he's damn close and has a huge Japan following too, which makes BDee more likely in my eyes than Isaac, though I want both, and K. Rool first and foremost who seems to be leading in 1st party newcomer votes East and West which makes me very happy.
I just...I just KNOW Wolf is coming and I hope he is. It feels so wrong to have Lucas and not Wolf, those two I feel are a bundle package of essential Brawl vets. We have plenty of Pokemon (sorry Squirtle and Ivysaur, though I'd be mad down for Ivysaur) and Snake has the Kojima/Konami kurkluffle going against him, and Ice Climbers with 3DS limitations. I'd say for any returning vets, that goes to Wolf without a doubt. What I AM surprised about is how Pichu seems to be climbing in the outtake polls, and is popular in Japan (like all the other veterans). He was my main in Melee but I had serious doubts he'd ever come back since he wasn't even considered for Brawl like other vets (and was rumored to be replaced by an Ice Climbers esk duo of Plusie and Minun)