I coordinate my kids more often than you do and do for Halloween also.
Year 1 w/ two: Mickey/Minnie(DH *loves* mickey so it was for him. )
year 2: Cinderella(dd's choice) and "gus" the mouse
year 3: they were both penguins(a FamilyFun idea)
This year I'm getting them excited about being a ladybug and a bumble bee. Just need to figure out how to make the costumes happen. I like to make them myself.