Possible Clues:

• Subjects of many viral online videos
• It left Broadway on Sept. 10, 2000
• Musical set in a junkyard
• Title pets in a Lilian Jackson Braun mystery series
• Reflective semiprecious stone
• Tabbies
• Feline mammals
• Musical with the song 'Memory'
• Musical based on Eliot poems
• Musical with meowing