Gadheras
Squire
If I can give a suggestion to this.
I know a while back there was a bug allowing you to recruit minor factions to your kingdom and make them vassals. I think this should be a feature. I believe in my opinion that currently it isn’t easy to find clans to join your kingdom. Having to ability to recruit minor clans to your kingdom would be nice. I think there should be a factor to keep culture in account and clan level for the minor faction. When a minor faction is recruit to the kingdom another minor clan is created randomly to replace the one that was recruited.
As far as I know. These mincor "mercenary" clans doesn't have any females though. They are all males. Recruit these will give you the same problem as you get when you promote a companion and make them a noble. You end up with a low tier clan with just dudes in it. If you want to play a long game and see these clans grow and propser, they need females to marry into them. Of which is a rarity in the game.