Susan Blu, Russi Taylor, and Pat Musick all reprise their respective roles from Scooby-Doo and the Ghoul School (1988) as Sibella, Phantasma, and Elsa Frankenteen, respectively. Marilyn Schreffler, the voice of Winnie from the film, had passed away nine months before it premiered and Patty Maloney, the original voice of Tanis the Mummy, had since retired from acting, so their roles were taken over, respectively, by Natalie Palamides and Kristen Li.