I think we'll definitely see at least one more newcomer before E3 and some more veterans.
I'm guessing we'll get Diddy sometime this month. Yoshi will likely be the only one in March. Lucas and/or Ike in April. Wario in May for Mario Kart, and perhaps the new retro character to coincide with NES Remix 2.
The E3 lineup will likely be Pac-Man and Mii (if the rumours are true).
And then a couple remaining vets like Ice Climbers, Metaknight, Zero Suit Samus, Sheik and finally a revamped Ganondorf to act as the main villain in the video.
More characters will trickle out afterwards likely with Falco, Mr. Game & Watch, Ness and Captain Falcon.
There will probably be one more newcomer reveal before the game is released. King K. Rool and Ridley are obvious fan favourites on this site, but they would need to release one last character to get everyone talking. Or if they don't want to release another newcomer before, a reworked Snake would get the people talking.
So ideally it would be a late August or September release for the Wii U version.
The 3DS would be released a few months later. This would help push Wii U sales making it the only option first. This big of a game being released on both platforms at the same time would result in many people just picking up a copy for 3DS, instead of actually going out and purchasing a whole new console for it.
Once the game is released the final hidden characters will be revealed until it comes out for 3DS.
We will see the characters people had at the bottom of their lists for returning like R.O.B, Wolf, Pokemon Trainer (with the same Pokemon, but showcasing Mega Evolutions as a Final Smash) a rejuvenated Snake and the epic return of Jigglypuff.
And of course the rest of the newcomers.
