P.W.
pony tail tied with a scarf if she has long hair. a white blouse not tucked in and rolled up jeans. Keds like sneakers with white socks. She can wear jewelry if she likes, but to really top it off go out and find yourself a cheap pair of glasses that are kind of wing tipped or jeweled. Voila! You can probably borrow everything and not spend a dime. If she really wants to wear a skirt I'm thinking you can get a cheap one at goodwill store and paint a poodle with craft paint. Or if you can sew get some cheap felt to make the skirt.
Of course brother should roll the sleeves on his white t-shirt, and if you can find some candy cigarettes be sure to tuck them into the arm of his rolled up sleeve. greased hair combed back of course.