At Christmas, I tell Becky that Santa Claus delivers presents to everyone to celebrate Jesus' birthday because it's the most important birthday we can celebrate!
The Easter Bunny brings candy to represent the "sweet" salvation that Jesus provided by His Resurrection, saving us from damnation for our sins by believing in Him.
Halloween is making fun of the evil spirits who are upset that November 1st is All Saints Day. That's why we dress up silly and have fun. I do not permit scary or evil costumes though.
I think it's safe to say that Becky has reached her last year of believing in the fables part of these stories, but she has retained what the true meaning of the holidays are, which is the important thing!
True genius there. I kinda did similar things with Myranda. I think it helped her to hold on to the "fables" longer too. Knowing there was a meaning.