There is no such thing as YELLOW baboon. I have been going to the Kruger Park game reserve for about 60 years now, and I have never heard of a Yellow baboon. Don’t know about Luangwa Valley. It really is a bit strange this yellow baboon.
There really called "golden" baboons. There more yellow when there young then they take on a golden color as they get older. So the young are called yellow and the adults golden.
I just recently watched a lot of the same footage with another video, but with a totally different story. But In that version, the little white nanny baboon is instead low ranking.