The Simple Sundress is a bit snug, as well as too short. I did manage to do up the snaps, but the bodice could really benefit from being made a bit wider, especially if some sort of top will be worn underneath. To widen the pattern, I'd suggest inserting 1/8" into the middle front of the bodice, and adding 1/8" to each side of the center back. You can the lengthen the bodice and skirt to get the desired look.
Hopefully this will help anyone looking for a pattern to make something for their KIDs.