Cartoonpets (All of the productions)

The Cartoonpets (Muppets)
Mr. Happy (from The Mr. Men Show) as Kermit the Frog (Kermit and Mr. Happy are both perky)

Little Miss Sunshine (from The Mr. Men Show) as Miss Piggy (Miss Piggy and Miss Sunshine are both the main girl)

Ed (from Ed, Edd, n' Eddy) as Fozzie Bear (Both lack intelligence)

yet to come