Visible crew/equipment: In the scene when Kermit confronts Doc Hopper he comes walking out of the bar. If you look at the top of Kermit's legs when he walks out, two pair of hands can be seen moving the legs.
Visible crew/equipment: In the scene where Kermit meets Fozzie, when Fozzie tosses the rubber chicken over his shoulder you can see Frank Oz's arm and where the glove ends.
Answer: Fozzie did not mean to sing the National Anthem. He simply wanted to sing something patriotic, since he was so moved by the scenery.
Matty Blast