The Princess Bride!

Kermit as Westley

Miss Piggy as Buttercup

A human actor as Prince Humperdinck (idk who, open to suggestions)

Fozzie Bear as Vizzini

Gonzo as Inigo Montoya

Bobo the Bear as Fezzik

Sam the Eagle as Count Rugen

Dr. Bunsen Honeydew as the Albino

The Swedish Chef as Miracle Max

Beaker as the Impressive Clergyman

Satler and Waldorf in place of the grandson