I don't know either, but think for a moment. Disney got The jim Henson Companys ownership of the Muppets, not the entire company. If Disney were to get the rights to certain productions just becasue a character that is considered a Muppet made a significant cameo in it, or just because the word Muppet is in the credits, then Disney might as well buy the entire company (or at least everything besides TimePiece, the Cube, Youth '68, Family Rules and anything with creations from the creature shop).
If Disney got productions based on minor appearances of muppets, then Disney would have gotten everything. Many characters from The Muppet Show frequently appeared on The Ghost of faffner hall and Mopatops Shop. should disney have gotten the rights to those shows? kermit was a main character on sam and friends. shoudl disney have gotten that? (in a perfect world, yes, in a normal world, they didn't) jaques Roache appeared on The Jim henson Hour but later had a more major role as Yves St. la Roache on The Animal Show. should Disney have gotten the rights to the animal show? (more likely, Henson probably owns the rights to this character) The swedish Chef made regular appearances on Donnas day after the first season. Should Disney own Donnas Day? (i haven't seen the show, but I think his appearances are more like guest appearances, and Disney doesn't own any of the muppets guest appearances on any show, except the ones that Disney already owns).
I don't think crossovers should count. A Muppet family Christmas, The Muppets: A Celebration of Thirty years, The Muppets celebrate Jim henson, the sesame Street character appearances on The Muppet Show and Muppet Movies and Sam The Eagles guest appearance on the animal show are more like cross-over appearances, and ownership shouldn't be a problem. Disney owns most of those productions because they use the muppet name and because the muppets are more prominant than the characters from other productions (in A Muppet family Christmas, the sesame street characters don't appear untill maybe the second half of the special, the fraggles don't appear untill later, and doc and sprocket are supporting characters).
I think Disney would have owned the Dog City episode of the Jim Henson Hour (which heavily featured rowlf) if it weren't for the fact that it was adapted into a saturday mornign series. I am not sure whether Disney would have gotten The Christmas Toy if there was no Secret Life of Toys.