I'm considering something else too. I just need concept sketches if anything of our species if this goes well.
Also, I hate the word witch. It's overdone and overused and has inclinations towards being devilry, rather than positive. I'd prefer the word mage, with three of a selection, dusk mages, dawn mages and twilight mages, it just means in between. I've never actually fully done it, but I'll explain more if you want to know.