You could try to find an existing family, take over a character that has a wife/husband and then chare that code to the fiance. Inbreeding is a thing but mjeah..
Really doubt there will be a Waerd, Janoa couple ready to take over tho.. as Waerd do not mingle with other tribes and do not even speak with Janoas.
So most likely you will have to start as same or even friendly tribes to have an easier time. Orphanages do not hold children from tribes not belonging to the kingdom, and you will have a long way to walk before you find eash other if you start in far off tribes. No maps, plenty of predators, starvation, burning sun, freezing nights, hostile guards...
With Bloodline packages you get to rename the first family you join but if you marry you'll waste one of the surenames. Still, small price to pay to get in on the action a bit faster.