I'm flying blind. The reason I have to fly, despite the blindness is that since this is Christmas time many Bayeyi will be "home", and therefore can check on the truth or otherwise of my SPECULATIONS.
There are three closely related Kalanga words, which I believe apply to Bayeyi: KU KOBA, meaning TO DIVIDE UP (and share among several people); KU ABA, meaning the same thing; and YEI, meaning THIS ONE.
The person conducting the sharing exercise could be called NKOBA or NKOBI. He/She could even be MOKOBA (when "Tswanalised"). The same person could be N'HABE, from the verb KU ABA. When sharing out cattle or something similar, the person would say "YEI ngeya woyu, YEI nge ya woyu!". So could it be that just like the Hottentots, there is nothing derogatory about the word "MOKOBA", that in fact that's who they are?
