Thanks, Atnas. I'll focus on finishing the hair for now and think it over. I know a lot of people dislike dithering in any case other than adding texture.... Personally I'm neutral about it, but I want to find a style that will be well-received. I think once I add some texture to the hair, It will be easier to see which technique will better suit the piece as a whole.
I like a lot of your changes to the girl, but I want to keep the green skirt thing if at all possible. (In concept, it's a "utility skirt" with pockets to hold all your gear.) I'm not sure if you got rid of this intentionally or it was simply unreadable. Here's an update: