IronMan said: "I don't know about Rashad's stint, but in the original cast it was Maureen Davis, the actresswho played Sleeping Beauty (only appears once at the end with Snow White, and also Bernadette's u/s) that doubled her for the change. Her face was covered by a mask and hood so it wasn't really seen;I can't imagine why they would have had to make any changes for Phylicia."
I've never come across Maureen Davis listed as a Witch understudy. When the show opened, the Witch understudies were Suzzanne Douglas and Joy Franz. Betsy Joslyn became the Witch standby after a couple of months (with the two understudies still listed as understudies), then of course she took over. When Marin Mazzie replaced Pamela Winslow as Rapunzel, Mazzie became a Witch understudy, with Douglas no longer an understudy. Mazzie once told the story of having to go on as the Witch during her first week in the show as illness was going through the cast, and both Joslyn, who was then the full-time Witch, and Joy Franz were out.
Maureen Davis understudied Little Red and Rapunzel and, oddly, Snow White.