So in addition to Statler, Waldorf, and all the other characters mentioned so far, I think we oughtta get some dialogue from the Muppet Newsman. I can definitely hear him being one of the characters to yell, "Jackpot!" during a round of multiball.

Band rehearsal/Electric Mayhem: Hit the top right corner bumpers to help the Electric Mayhem rehearse for their act. Once they're ready, it's time to take to the stage (shoot the scoop to start a mini game). Once started, shoot any ramp or loop enough times to beat the mini game.