Songs that are a requirement:
Dickie Valentine - Christmas Island
Holly Jolly Christmas - Burl Ives
Here Comes Santa Claus - Gene Autry
Happy Holiday/The Holiday Season - Andy Williams
Santa Claus is Coming to Town - Jackson 5
White Christmas - The Drifters
Must be Santa - Mitch Miller
Christmas (Baby Please Come Home) - Darlene Love
Sleigh Ride - The Ronettes
Merry Christmas Baby - Otis Redding
That's the list. Everything else is up for debate.