Roger that. Lets see how my over the internet diagnoses goes.
I'm pretty sure the issue you are having is the engine doesn't crank over. The starter motor fails to engage.
It sounds like you have the same loom as your car as it plugs in and the ECU number looks like its correct. This is important to check as later Ecu plugs in but a few different pins makes it not work. (I'm doing a car in Poland atm like this )
Step one , does the engine turn over by hand? I would put a socket on the front pulley to confirm the engine rotates.
There is a large black plug at the back of the engine which joins the main engine harness to the starter harness. The large black wire is the start trigger. I would check this is plugged in. It also allows a place to jump a trigger in to check the starter motor but its easier to do inside the cabin.
This same large black wire is inside where the engine harness plugs into the body harness. You should have a 14 pin plug (two rows of vertical small pins on the outside , both sides , then two large pins vertical in the centre) Top one of the large is large black starter motor trigger wire , bottom is black/orange power to coils to putting voltage to incorrect wire shouldnt cause an issue.
I would be unplugging this plug and firing some voltage to the starter motor to confirm the starter motor works. If not, diagnose a failed starter. If it cranks over with this jump its good news.
I would then reconnect the plug with the start trigger and confirm you get voltage when the key is in the start position. At a guess it wont have any. I suggest the issue is the old loom had the bypass for the start inhibit in the loom. Did you remove the transmission loom? If not put a bridge between the black and black/white wires on the selector switch . These are the two with the large terminals. If the transmission loom is removed then find these two wires in the engine harness to body harness plugs, join them and hopefully the car cranks over. They are in the same start plug under the dash but just as a warning the tacho wire is also in this plug and is black. I would avoid getting this wrong. If this circuit has been bridged correctly already then I would be looking at the starter relay.
Just as a note I normally sell diagrams and info (I do 1uz conversions for a living, youtube CartuneNZ) but today I'm feeling generous. Good luck and let us know how you get on.