Somehow, it always triggers my skepticism when supposedly sociobiological or evolutionary anthropological or evolutionary psychological arguments are brought up. My suspicion is that it is far too easy to simply pack in the story you want to have in there. I can think of dozens of objections to your description. For example, in small groups, the social game in terms of status may not be that complex, and the choice for pairings may be very limited.

I'll leave it at that because I don't want to write a novel. But when I look at your description, I don't see any plausibility at all. I only see projections. Like in The Flintstones or in old movies about Stone Age people, who have strangely short haircuts and go hunting the way people go to work today. What I mean is: the social dynamics you're assuming here may be primarily shaped by your experiences in the present and are far from as universal as you believe.