As shown in the picture, just above the drive mode on the driver display there is the icon of a person with the word "OFF". Is this something that turns on automatically? Is there an option to turn on? Maybe in it is only "ON" when it is dark?

I did call Mercedes EQ line, and after about 15 minutes of research, they had no information.

I believe what you are seeing is the Occupant Presence icon. The picture below is out of the EQE SUV manual.
There are so many -- and so many obtuse -- icons that I find it's difficult to remember them all, let alone pay attention to them all. TMI!