If the ignition, headlights, A/C and such parts were powered up when the crash happened, as wires were crushed together, shorted to earth and circuits were cross fed by incorrect voltages and consequent currents flows, there is a potential that your ECU, BCM TCM etc computer modules may have been hit by incorrect voltages etc.
If the motor bounced around and damaged wiring looms at the back of the motor that damage may not be visible, and this could cause issues with feeds to the transmission, and motor's overhead components such as ignition coils, injectors etc. I guess you have proved all of the fusible links at the battery, engine compartment, and all fuses including the cabin fuses etc are intact.
Maybe getting the computers checked out might be a good starting point.
If you can establish eg. the fuel pump is working, pressure regulator, fuel injectors etc are working by independent testing then the ECU could be the problem.
Can a Tech2 or scan tool be used to check that all the computers are communicating?
Perhaps DTCs may come up when you try to start the motor and give you an idea where to look.
Holden have replacement wiring looms, not real cheap, but hidden broken crossed up wiring still inside the loom's wrapping may not be obvious.
I investigated an engine loom for my VZ SV6 and Holden wanted about $380 from memory. It finally worked out being the ECU slowly failing over a period of about 6 weeks. The engine loom had relationships with the transmission across the rear of the motor, plugs, injectors, purge controls, throttle body, camshaft actuators, crankshaft sensors, BCM, alternator, A/C etc. etc.
I think Holden have a CD of the VZ complete service maintenance manual, which includes wiring diagrams etc., - not cheap I'm told.
