My theories in order of your questions:

1. We see them acting like the help only when the MC is (going) to be there. They’re playing their role so he doesn’t get suspicious. I think as soon as he is gone they go back to doing whatever it is rich white people do.

2. They view the black mind as inferior, but the black body as superior. You can see when they invite everyone over to the auction, they’re very curious about his physical traits and build, but never ask about school or anything like that.

Idk it’s been a minute and I’m not a critic, but I thought the movie was pretty good.

A woman bird*