In the last scene where everyone comes in the apartment to celebrate Christmas, Rowlf the Dog comes in and says the line, "Let's trim the tree"! Rowlf hasn't spoken a line since Jim Henson passed away. This was out of respect for Jim as Rowlf was one of his key characters.
During the last song, "My Best Christmas Yet", The Swedish Chef is in the background greeting a turkey and giving it a hug. This is the same turkey the Swedish Chef almost cooked in A Muppet Family Christmas (1987).