WWE will be going heavy on the Halloween theme tomorrow, including a Divas costume contest that is in the current draft of the show.
Three Muppet Performers that I know of are scheduled for Raw - Steve Whitmire, Eric Jacobson and Bill Barretta, as well as some right hands (performers who operate the other arm of the Muppet while the primary performer manipulates their voice and left arm). That would mean that pretty much all the major Muppet characters except Gonzo would be available for WWE to use. I haven't heard if Dave Goelz, who portrays Gonzo was booked or not.
One segment that The Muppet performers were asked to prepare for involved Stadler and Waldforf doing commentary for a match, which I can only assume would be the Michael Cole vs. Jim Ross segment.