Personally I say go for it. It sounds like you have good intentions which is the most important thing. I don't think you're taking anything away from people with DID - there is a unlimited amount of art to be made in the world, and I appriciate anyone trying to minimise the misconceptions of DID because it's not an easy job and it'll take a lot of hands working together to help people understand that we're not monsters. As someone in the comments say, don't depict us as monsters, or broken, or possessed. Don't depict us as a super hero either, it's not a magical power that someone should be jealous of. Can't wait to see what you come up with, and feel free to PM me if you want to talk :)