Problems I see....
Without the security code for the bcm you can't program a new key, normally to add a key you have to disable security with an already programmed key then put the new key in and program it with the tech2, you don't have the matching fob for the bcm so you can't do this.
To program a new blank key you need the security code for the bcm if you don't have a fob, for this you need the vin # of the vehicle it came from, proof of ownership and then get it from holden.
A key from Mr Minit is not going to work either, they use a reader to copy the old key then program a new blank, the steps to make it work is not programming it at all, it's simply linking it to the bcm for the remote buttons to work (if it was blank it wouldn't start the car or it'd set the horn off as soon as it was turned in he ignition)
There is no other way to program a new key to the bcm, no tricks of holding your tongue in your left cheek with your legs crossed while sing the national anthem backwards turning the key on/off and counting numbers will not change this.
I guess you could make a deal with the devil but that'd be pretty high stakes just to start a car.
To link the bcm & ecu, don't you have to disable the security with the key?
If it was as simple as you seem to think a lot more commodores would be found stolen and burnt out.
The security systems used in the US on the GTO is completely different to that of a commodore.