This could easily be a very simple costume - curly wig, some blue dye, black zentai, red lines, the end.
But that's no fun 8D
The definite challenge here is going to be the wig - instead of basic little curls, I want to get the giant fluffy cloud look she has going on. So far the best idea I've had of this is to get a base wig, then using ridiculous multitudes of extensions, make puffy round parts with a 'dreadlock' effect on them. Combine this all somehow, spray on tints of blue, and voila.
Easier said than done xD
Other thing I want to do here is get the red strips on the costume to light up - so far I haven't found a way to do this. But haven't stopped looking yet!