Can you purchase some hot pink (fuchsia) fabric that is similar to what's she's wearing? If so, then you could cut off the lower part of her costume and replace the lower half with a skirt made from the new fabric (minus the long slits in the front). May need a small slit on the side or in back for walking/dancing depending on how you make the new skirt... straight or with some fullness.

Another thought...you could make the one she is wearing shorter (cut it to above her knees). Use the fabric you have cut off to fill in the open spaces on the now shorter dress. Maybe even add a white ruffle (like the one that's on the bottom of the all white dress) to the bottom of the shorter version of the fuchsia dress. That would balance nicely with the white in the headdress.

Couldn't she wear some colorful (or skin-colored) tights instead of shorts? What about weights on the hem to keep it hanging down & a lining on the panels to give them some more body?

Hope the show isn't already over....