yes you could use a current sensing relay although the ones in a fridge motor are AC and are non adjustable,
this would work,
AIROTRONICS HCSDC045A Relay,Current Sensing,45 Amps | eBay
although I dont really see a need for it, I would just wire a DPDT momnentary switch in there,
and yes the immobilizer can be programmed out so you no longer have to worry about it but depends on how much $$ you want to spend,
as for the window drop on door open, that will require a bit more thought, you would have to use a capacitor resistor combination to give a time deay or use a timer circuit using a 555 IC driving a transistor output to a relay,simple just needs some thought