Correct me if I am wrong, but I thought that in kingdom matches are preferred to out of kingdom matches. Though I have seen Ira among the Aserai many playthroughs so perhaps that is not the case.
Either way, more women are still needed among companion clans or they will just steal all the women from other clans, this way it becomes a somewhat equal share.
How would you like for companion clans to spawn?
If they do, it's not a significant preference because, by the end of my first playthrough, there were more ethnic-Aserai in kilts, togas, and corsetted dresses than there were in keffiyehs and caftans lol. Even by the second generation, intermixing was commonplace enough that I vaguely understand TW's alleged decision to make Culture be derived from the father instead of the mother (I dislike this change, if it's real, since I actually enjoyed seeing how effectively new cultures spawned over time) if ethnic homogeneity is preferred in-universe. Heck, Ira married Tegan fen-something very early into said playthrough, and I must say I'd appreciate it if they changed the marriage rules for only-daughters so that the in-universe heir to Emperor Arenicus actually remains his heir without having to risk becoming a lifelong spinster because her mother has a long lifespan lol or else be effectively scrubbed out due to marrying into another (potentially foreign) clan.
There's LOADS of women in-game so I can't say I care if companion clan men are sex-crazed monsters who seduce and rapidly impregnate every young female across Calradia lol. If anything, this is actually desirable because it means less clan members for non-loyalists and a bigger next generation for elevated homies.
Personally? I'd like it if clan spawns were age-based. Like, if you elevated a 18-34 year old, they'd start off with a mother, father, and brother; if you elevated a 35-50 year old, they'd start off with a wife/husband and two adult kids; f they're elevated 51+ they start off with a wife/husband, two sons/daughters and their wives/husbands, and finally a pair of grandkids per couple. This would incentivize raising old people since already have a "secure bloodline" while young people, though more insecure, have a back-up sibling plus whatever kids are created by their parents. This would be more immersive to me, personally, because a lot of companions speak of having families but the newly created clans are vague on how they're related, so we can only assume they're siblings or cousins or something, whereas a defined family tree like I described would make it clear they do, in fact, have home lives outside of their subservience to the player lol.