Nothing, because none of the things in Song of the South that are considered racist are featured in the ride, and nobody considered the attraction racist simply for being related to a film that has racist elements in it until Frederick Chambers posted his idea for a retheme of the ride on Twitter.
Song of the South IP is going away. That's the decision. It's not about finding a new place for Tiana, but what to put in SM when SotS is gone. And it's going to be gone.