I'm not super picky so it's really whatever you're most interested in. I have a pretty angsty writing style as I'm addicted to tragic characters but I'm flexible to any genre. A lot of what you listed sounds interesting. Of your pairings, I wouldn't mind the Demon x Human. In opposition to you, I actually prefer to roleplay the more aggressive dominant character so that works out haha. A lot of your brief scenarios sound pretty entertaining too.