Just my guesses:
Next Zumba game. What, the Zumba fitness game?
Mist Walker was rumored to be working on some Wii U game. What rumour?
Ganbarion (Pandora's Tower) co-developed Wii Fit U so they could be working on a Wii U game. No. They just finished working on One Piece Unlimited World and Wii Fit U, so if they're working on something new, especially for the Wii U, it won't be ready before 2015.
Headstrong Games (Batallion Wars 2, House of the Dead: OVERKILL and the Art Academy) was rumored to be working on something. That's Art Academy U.
Treasure . They are working on something for 3DS right now. They're already done, but their next project, whatever it is, probably won't be revealed before a very long while.
Artoon (fling smash) could be working on something. "They"'re making New Yoshi on 3DS.
Sandlot (Zangeki no REGINLEIV)
Namco, because its hard to believe they are not working on another Wii U game. They already got their hands quite full with the new Super Smash Bros game, and also the other Wii Sports U sports.
Sega There's that 3rd Sonic game, yeah. But other than that nothing to see.
Capcom, because if Megaman is in smash and Nintendo isn't getting a new megaman game someone needs to be fired. Yeah, and Snake in Brawl meant a MGS game on a Nintendo console, right?... Though I agree, there was MGS3DS.
Team Ninja said last August that they will continue support TN is part of Tecmo-Koei, so it's not really up to them to decide whether to continue support or not.
Tecmo, because Nintendo owns Fatal Frame now What does owning an IP got anything to do with anything?
Nintendo really needs to get with indies and fund some exclusives like they did with Platinum . Hell pick up where Sega left off with the Wii and even fund a High Voltage Software FPS just put the Nintendo polish on it. Same could be done with getting n-space to make a Wii U game.