One other thing, they talk about how Matt Robinson continued to voice Roosevelt Franklin in the "classroom" sketches after he was no longer playing Gordon -- how long did that continue?
Also, Roscoe Orman was part of these as the voice of Hardhead Henry Harris. But those sketches started before Roscoe Orman was on the show -- I know he and Matt Robinson were acquaintances and I read at least one account that said it was Matt who told him they were recasting Gordon again. But it seems unlikely that Roscoe would have been in Muppet sketches before he was even on the show.