TBH, we don't actually know that the wives are the Branch Leaders in the Khun Family. That's just fanon.
The only actual Branch Leaders we've seen of the Khun Family is Asensio. While he may be an exception as he founded his own Faction/Branch, the available evidence supports the notion that the most powerful sons of Eduan are what forms the Branch Leaders.
AA told White that he had a connection to his Family's "Leaders":
Presumably, he was referring to the Branch Leaders of his Family here.
Said connection seems to be the older brother that assisted him on the Hell Train:
SIU said outright that AA was keeping a good relationship with a member of the Khun Family that was "quite powerful":
SIU's Gossips
Source
Asensio reinforced this by saying that AA was working with a "dangerous person":
So by all indications, AA's patron is one of the Branch Leaders of the Khun Family.
(A more complete treatment of the topic can be found in the below thread):
A "Dangerous Person" In S3 E98 Asensio revealed that AA was working with someone that was "very dangerous": Previously in S3 E55 AA revealed that he had connections to the "leaders" of the Khun Family, and so he wasn't worried about Prime White: For convenience, I would refer to this...
mangahelpers.com
We're left with a situation in which the only confirmed and probable Branch Leaders of the Khun Family are sons of Eduan. The idea that the wives of the Khun Family lead Branches of the Family simply has zero basis.
The Khun Family is also a Family in which the Branches represent military units and the Branch Leaders are some of their strongest High Rankers.
As for the Lo Po Bia Family, separate from the Family Branches exists the "Lo Po Bia Army" and the "Main Family". These and not the Branches seem to constitute the main force of the Lo Po Bia Family (excluding the Family Leader).