Hi, Ren! Just some explanation about how we categorize things here.
1. Characters belong in the category for the film or TV show they debuted in. So Old Joe or Beggar aren't included in the categories for Muppet Treasure Island, anymore than we include Kermit for every movie. The occasional exception we make is for some TV series; Kermit is categorized for his original three main series (Sam and Friends, Sesame, Muppet Show) and we've also tracked for appearances in MuppeTelevision segments of The Jim Henson Hour and Muppets Tonight. But we don't have him in the categories for every special where he was the introductory host, for example.