Here are quite a few bio's of these lost characters:
LULU
Seasons: 31-33
Years: 2000-02
Lives: Sesame Street
Performers: Stephanie D'Abazzo
Description: Lulu is an Anything Muppet monster. When she first appeared on Sesame Street in Season 31, she is light-blue colored and had light yellow hair. Then, in Season 32, she is purple and had light purple hair on top. In Season 33, she still is purple and had light blue hair on top. She is a good friend to Elmo, Zoe and Rosita.
PAT PLAYJACKS
Seasons: 18
Years: 1987
Performers: Jim Henson
Description: Obvious host of 'Squeal of Fortune'.
THE 'F' CHEERLEADERS
Seasons: 1
Years: 1969
Performers: Jim Henson, Frank Oz, Carroll Spinney
Description: These Anything Muppets (the pointy green headed man, the round-headed blue man, the tall orange man with a few yellow and long hairs, and the purple man that looked like Roosevelt Franklin) that cheer for the letter 'F'.
Hope these would work...the classic 'F' cheerleading sketch from 1969 can be shown on the Season 31 episodes on Noggin.