Hi There,
These fridges come with a freezer compartment that is not removable. It should get down to about -16c.
These fridges have a mechnical thermostat.
The power consumption would be an average.
Airlock refers to the locking mechanism. This has been designed to make the fridge easier to open.
You cannot gain more space in the fridge when mounting it proud. This is just for how the fridge sits in the cabinetry. The door does not move.
Generally fitting a fridge in a 4WD  should be okay. You need to make sure the fridge is mounted securely.