The immobiliser module will prevent the starter motor turning, the ECU will prevent starting so presumably you need to delete the ECU immob function and then rewire the starter to operate without the key chip and code. Worth pursuing I think if...

Tricky one. I read that as 'even if the engine won't run you will be able to unlock the car by buying our product!' However, it won't fix the engine or unimmobilise the immobiliser.

All good for Fobs. No good for keys OP has lost key with chip in.

No, the coil is purely a coil. No coding in the coil and same on all vehicles. The chip in the key which matches the immobiliser and engine ecu has to be present as above.

The key has a chip in the black plastic part of the key. It is this chip that 'talks' to the coil and sends correct signal to the immobiliser module and then to the engine ecu. Without the chip the car will not crank over. Ignition will work OK...