Heidi needs a dirndl - you can make quite a good bodice out of crepe paper by cutting out this kind of shape, stapling the shoulder straps, reinforcing the front edges with card, punching holes in them and lacing ribbon through them. Wear over a white blouse and a cotton skirt with an apron.
Violet needs a gothy black or grey dress (get charity shopping!) and a hair ribbon - plus an invention...