They will definitely promote the heck out of these guys until the movie comes out. I just hope they can continue whatever it is they're doing.Everything they've been doing; Letters to Santa, Bohemian Rhapsody, virals, appearances, etc.; has been for the sole purpose of building a groundwork and a foundation and excitement for the movie. I highly, highly doubt that they're going to stop this momentum now, of all times. I've been told by a few different sources that this momentum will continue. I'm not sure about another major project in the works, but one would assume they'd be planning something since the shoot for the film is only 6-8 weeks.
The Halloween special keeps getting pushed back, and filming for the movie will no doubt push it back another year. But as long as the appearances keep happening, the virals keep coming out, and we release more and more Muppet stuff on DVD (still don't see why they can't release MT and TMS concurrently) they'll have a foothold in the market place. If The Disney Channel didn't turn into the alter of tween pop, they could have reran episodes of either show, AND added Muppet Babies to the Preschool line up. Hype is the key to this film's success. Seems like a big merchandising push is happening to, albeit slowly.
But as far as the film goes, there's really no time before the shooting to make the next big project. We don't want the next special to be rushed. So, any new projects before the film would have to happen after the shoot... and no doubt the puppeteers and crew will want a tiny bit of downtime.