From 1979, here is The Halloween That Almost Wasn't,
starring Judd Hirsch as Dracula, Mariette Hartley as the Witch,
John Schuck as Frankenstein's Monster, Jack Riley as Warren the Werewolf,
Henry Gibson as Igor, Robert Fitch as the Mummy
and Josip Elic as Zabaar the Zombie.
Thanks to HalloweenShows.net for the heads up on this oldie but goodie!