Yes theft or more likely damage shenanigans would eventually occur. and you would only gain the most if you parked your car uncovered outside frequently.
Your notes on my terms and such are correct, you are clearly thinking far ahead, I was just trying to keep the long post less long
While there is the charging danger, you could automate a case where it didn't exist and save on the inverter cost and 15% loss. Of course covering the car would require some safety.
My GM alternator as the OEM part for my car has the kill switch, a '93 Cadillac Deville. My only guess as to why is because the car's service manual has a number of procedures which require the kill so they added it as spec for easier service.
I was also thinking about the coolant heater as the best step. It seems you lose a lot of efficiency with the pan heaters unless your electricity is free.
Another nice feature about my big old car is that it has oil and transmission fluid coolers built onto the sides of the radiator. These has the effect of also warming those fluids during the winter.
Did you go with the inline heater or full version with the pump attached? Which brand? It'd be nice if I had a block plug to key into but this model engine doesn't have one.