I want to bring this back up as I catch up on the thread.There canonically no dragonborn mercenaries in Baldur's Gate. The are not mentioned. Even Decent into Avernus, where we actually HAVE Flaming Fist Mercenaries outlined, does not have a single Dragonborn. IIRC, there is a single Dragonborn in the module, but, not in Baldur's Gate.
If a player isn't mentioned in a game recap of a sporting event it doesn't mean the player doesn't exist. I don't know why the assumption is that every single possibility needs to be mentioned in a book for it to exist.
None of my characters are mentioned in official books, do they exist?