I have a Nova Air and here are a few clarifications:
1. Nova Air only has one button.
2. The case does need to make a contact with the Nova Air unit. There are three metal pins on the cover, making contacts directly with the left margin of Nova Air.
Photos:
Pins on the cover, and
receiving ends on the Nova Air
RE: BOOX Engineers - I did ask them when they can let us remap the physical buttons on the magnetic cover. And, they went silent as always.