Here's a clip from the owner's manual about the shift lock.
The car has to be in (P) or (N) in order to crank. I forget if that function uses a sensor in the gear shifter or the one at the transmission end of the shift cable. When I get a chance, I'll look it up and post if nobody else does.
If you turn on the ignition with the seat disconnected, it WILL trigger the airbag fault. There are some reasonably priced diagnostic code readers that will reset the light. I use an
Autel MD 802.