I think, given what ONCE tends to do, if they are going to pull from anything not of the book it’s going to be the 1938 movie. It’s the thing that most people think of when you say Wizard of Oz. Second to that is Wicked. Most people probably haven’t read the entire Oz corpus, I know I haven’t. But you better believe I can quote the Judy Garland movie. And while A and E do their homework, at the end of the day it’s about appealing to the largest group you possibly can. Thus, their spin on Ariel’s story and character is basically DISNEY. She’s got her red hair, her purple bra, she steals things, she’s got a fork and her Prince is Eric. Yes the HCA tale is depressing as all heck, but there wasn’t a whole lot drawn from that at all. They went with what people expected when you say Ariel: The Little Mermaid.
Look at the way Mader is costumed: it’s a modern Gulch. If she HAD been Cruella, she’d be decked out in furs and her hair would be all sorts of crazy. You have to give your audience some points of reference.