Oh, honey, keep in mind that Due South's pilot aired 18 1/2 years ago and the fandom's existed since the Usenet days. Don't fret over whether something's been done before. Focus on making it what you want it to be. Granted, it's nice to check and see if you're accidentally echoing something someone else already wrote, but as Oliver Welles would say, "That just proves it's a good idea." You can absolutely reframe it in a way that makes it your own. Yay transformative work! :)