You're very welcome!! The Witch of the South is one of my favorite characters from the book series, and it's such a pity that she's not always represented in the way she should be.
I agree with you about the diversity and tolerance bit! Baum really made it a point of his to make sure that everyone in Oz was kind and accepting, which I love. Like you said, in a world with so much magic, why are skin tones an issue?
I'm working on my own comic adaption of the first book, and I've made it an intention of mine to give the characters all manner of skin colors- Glinda is very Persian-Indian inspired in my version, so she will have darker skin.