They would have to do it frequent enough and spread out far enough to not cause crowding. I could see this working though. Cinderella and prince charming out on the balcony of the castle saying hello to people or Belle and Beast dancing in the castle. They could also use the main street vehicles to have Marry Poppins and Bert wave to guests as they go by a small show on the train station platform by the Barber shop quartet.Perhaps they will have tableaux scenes of the characters, kinda like flash mobs, where the characters will be able to walk to a spot, have a “moment”, and then walk away while not actually having any human contact. Kind of like the Kylo “moment”, but for each character (Jack and whomever sword fighting in Adventureland, royal couples dancing or whatever in Fantasyland, etc.). It would reduce the amount of actors and actresses portraying each character to one, allow for shorter work hours for the attendant roles, and avoid the “parade” mentality if done as a surprise.