i think Little Dancer is much better than Marie, Still Dancing. There is a TM for "little dancer" and i wonder if that is the reason for the change.
I did find this interesting article on Degas and whether he was "active" with them. "Laurens posits that it’s highly unlikely Degas sexually abused 14-year-old van Goethem, because Degas was a well-documented celibate, his abstinence rooted in a disgust of womankind. "
I don't think Degas pursues Marie in the musical and is more of bystander to her interest in the younger man.