People don't necessarily need to conform to his particular fashion choices--as he's most into men's fashion for his own purposes--but he has respect for commitment to an ensemble theme. Like, if someone were dressed as a lumberjack and therefore were covered in sawdust, that would make sense to him even if he wouldn't want them sitting in his chair. He would sneer at them for not wearing work boots with it, though. That violates the theme! If someone wore every article of clothing in a different pattern, that is a theme, but if they repeat the pattern even once they have violated it and that is sneer-worthy. People need to commit, gdi
A large portion of his underlying structure is in fact Prince Vassago, and is in fact a Prince of at least one Hell. The Kristján portion of him is only about 50, however, and mostly functions as an interface between his cosmic celestial function portions and everything else outside of him.
She sounds like someone he would definitely want to know professionally, especially if she could get him stuff like items to magically clean his clothes (as even dry cleaning puts strain on the fibers). He also does have a plant whose care he takes very seriously. He gives it bottled water because he is a douchebag.
They could trade in kind that way, if she needs to find a thing and has an item he could use.