Hope the baby is a girl!
well, WDW uses both sexes for Tinks flight...
I dont really have any suggestions, but I just wanted to say how jealous I am. I cant even get my husband to dress up!
Or...
Snow White
7 Dwarfs
Evil Queen as a Queen
Evil Queen as the Witch
Prince Charming
The Huntsman
The baby is an apple
or someone is the magic mirror....I would LOVE to be the one in the group who gets that costume!
OP...you could also (in Disney font) each have a letter on your shirt..spelling out :
WE LOVE DISNEY!
or
WE (HEART SYMBOL) WALT DISNEY
the baby could be the heart symbol....and unless you are standing in order,,,scrabble!

At least you would be in costumes that are ride friendly, cheap, easy to pack and really quick to put on!
personally. I love the Evil characters...you guys could each pick one and just be an evil theme for Halloween! There are SO many to choose from:
Malificent (Sleeping Beauty)
Evil Queen (Snow White)
Jafar (Alladin)
Randall (Monsters Inc.)
Pete (Goofy)
Cap'n Hook (Peter Pan)
Barbossa (Pirates of the Caribbean)
Cruella (101 Dalmations)
Lady Tremaine (Cinderella)
Yzma (Emporers New Groove)
Ursula (The Little Mermaid)
Shan-Yu (Mulan)
Scar (The Lion King)
Shere Khan a/o Kaa (Jungle Book)
Hades (Hercules)
Queen of Hearts (Alice in Wonderland)
Frollo(Hunchback of Notre Dame)
Gaston (Beauty and The Beast)
Governor Ratcliff (Pocohontas)
Chernabog (Fantasia)
Oogie-Booge (Nightmare Before Christmas)