Diane Franklin as Constanze?
She and Elizabeth Berridge were the finalists for the role of Constanze after Meg Tilly had to drop out. Forman felt that Franklin was too pretty for the role and cast Berridge instead.
So... if Elizabeth was the "quirky" Constanze, Meg would have been the "ethereal" Constanze, and Diane would have been the "earthy" Constanze. Not to malign Elizabeth, whom I thought was just fine, but I would love to have seen what Diane did with the role.