I don’t think it’s rude at all! Headcanons are headcanons for a reason. @nightmares06 writes Dean as straight and Stan is in a relationship by the time they meet in Brothers Consulted, so they won’t end up a couple at all in our stories, but it’s perfectly fine to think up your own versions of the story as long as you don’t demand we make it canon.
I can’t wait to write about Stan and Nathan, though. Nate’s just the right amount of chill to go along with whatever shenanigans his secret agent brings home.