Some elements of surprise during my costume design class: that my students had a good time and that they came up with some very interesting surprises.
I tell my students that I don't particularly like children in general, so if they're going to act like children, I'm not the teacher for them. This sounds rather harsh, even to me. But I suspect that young women of this age don't want to be treated like children, so this actually works out well for all of us. Whew! In return, they're willing to indulge my requests to draw their faces without looking at their paper; to abandon an idea that seems like a little old lady going to lunch with the Red Hat Society would think "was real cute."
Now. As for design: All found objects and hats from the thriftstore. Hot glue. Wire. A bag of balloons. Fabric remnants. Newspaper. Needle and thread. Duct tape. An old rabbit fur coat that I found in someone's garbage. Umbrellas. A crochet hook. A pot of lemonade. Fancy cookies.