Jewish conversation above was quite important,if for nothing else in a nomadic society, having plenty of "cousins" to defend the tribe. Witness Abraham and his 318 retainers. (Genesis 14:14)
(Without wanting to turn this into a biblical exegesis class...) This can be misleading if taken out of the wider Genesis story because it doesn't take into account Genesis 12:16 which says that Abraham acquired many menservants and maidservants in Egypt. And there are mentioned on several occasions his 'herdsmen' who may have been these Egyptian servants or local Canaanites employed for this purpose. So "the 318 trained men born in his household" that he called out in Gen 14:14 were probably mostly not Abraham's relatives at all!
Cousins were mostly important to Ancient Near Eastern tribal culture for marrying. And this is also reflected in the Genesis narratives. Abraham and Isaac sent their children back to the land of their ancestors to find marriage partners from amongst their cousins.
Most assuredly your analysis can be correct. But many may have married into the tribe
between the chapters indicated. But not to bicker. And returning to the land of their
ancestors is also common, as you point out, and used for defense reasons as well.
Who knows? Interesting concept in a discussion about in laws and the like.
