Everything is still speculation at this point. Nothing solid, not even the booking date or the start date. Some of the rumors:
Breakfast only
Breakfast and lunch
Heros only
"Boys" meal
Toy Story meal (which I would guess would include Jesse)
Pixar meal
One thing we know for sure was that they were hiring a Sarge character to lead an "exciting new character dining experience at Disney-MGM Studios".
The most popular guess seems to be that it will be Sarge, Woody, Buzz (although he does not do autographs, but he does have a stamp), Mr. Incredible and Frozone.
So, I guess we will see what happens, hopefully in a few days. I am still hoping they announce something on March 1.