Room redecorating advice!?

For belle you could go with a library type room with lots of bookshelves and books. Yellow is always a good colour for belle. For ariel you could have an aqua comforter and maybe an aquarium with blue on the walls. If you go with ariel make sure to do different shades of blue. Jasmine is probably the hardest. You could go with an arabian theme. purple is always a good colour for jasmine but may clash with the the arabian theme. Whatever you do depends on your style and budget. Hope this helps!