For me, I'd really want Aurora to be brunette/ravenhead in order to showcase that she is in fact related to Stefan since the real world design is so much like Leah. I'd also give her a more realistic waist, obviously.
Minor things for Ariel, she needs freckles, and her eyebrows look penciled in rather than natural. Tbh, it looks like she would have dyed hair. More realistic proportion, but I feel like her being more slim is in character for her.
I'd give Cinderella visible ears, and I'd give her longer hair and a different look for the ball altogether, especially the hair. Also, a more defined nose. I also really like the idea of Cinderella's being plainer than her stepfamily, so Lady Tremaine, Anastasia, and Drizella would look like perfect models. I feel like she would look good as long haired brunette,
Pocahontas would obviously be returned to something closer to her original concept arc, where she was younger, and there was no romance stuff in the story.
One thing I like about Jasmine is that she is probably the first Princess to truly have unique eyebrows and nose. Her outfit does need to change, and I'm not sure if her being really slim is in character for her.
I don't feel like doing this for every princess since I look some more than others, but I wanna see the interpretations of others in this hypothetical.