I could see the Mayhem performing "32 Footsteps", with Floyd and Dr. Teeth sharing lead vocals. (Dr. Teeth particularly on the "Bing bang bingalong..." part.)
How about:
"A Kiss To Build A Dream On"--Louis Armstrong (Dr. Teeth on vocals, Zoot sax solo)
"Do You Know What It Means To Miss New Orleans" (I used this for my Harry Connick, Jr. outline, Harry and Floyd share vocals)
"When The Levee Breaks"--Led Zeppelin (Janice on vocals, Animal drum solo)
"Moby Dick"--Led Zeppelin (Animal drum solo)
"Hair" (Floyd lead vocals, interrupted by the giant monsters, Gorgs, and various other hairy things)
"Great Balls Of Fire"--Jerry Lee Lewis (Dr. Teeth on vocals)
"No Such Thing"--John Mayer (Floyd on vocals)
"Tripping Billies"--Dave Matthews Band (if I ever write a Muppets/Dave Matthews outline this'll be in there...more opportunities for Zoot to do a sax solo)
"Everybody's Boppin"--Lambert, Hendricks & Ross (Floyd, Janice and Zoot vocals)