The girls are going as Sally Brown and Snoopy from the Peanuts gang. You'll have to be satisfied with Instagrams of their costumes for now.
Aren't they the cutest?
Ellie's costume: Dress: Pumpkin Patch, Socks: Target, Shoes: Payless
Olivia's costume: White sleeper with a black flannel spot and tail sewn on (not pictured); Hat, scarf and Woodstock: Build-A-Bear Workshop. Yep, she's so tiny that she fits into teddy bear costumes.