Just a note: the actual tile for border marquis is margrave.
Edit: sorry, I know I am annoying, but I would like to point a couple more things. Your grace is only for dukes; your lord or, better, your lordship are the appropriate titles. Also, please use the proper pronouns. You can't have a character refer to the lord whike to someone else saying your lordship; use his lordship.
Thank you for the translation, I hope my points will help you. 😊