All of them!
Each week the episode would focus on one character's life inside and outside of the muppet boarding house (from MFS) and working on the show at the theater (from TMS). So one week it would be mainly a Kermit story, another week a Gonzo story, an Electric Mayhem story, then another Kermit story, a Bobo story, a Johnny & Sal story, etc. Along the way, they would interact with other characters inside and outside of the house and theater. Cameras would follow the life of the Muppet gang as the live and work together and go about "life".
Similar to the idea for a Muppet Family Sit-com layed out in
this thread, but with the "reality feel" in terms of realistic sets, locations, and camera work.