i have seen an aftermarket kit fitted to the same vehicle, the speed sensor was mounted to pick up from the drive shaft and it had a second cable fitted for the throttle.
i have swapped ECUs from plant engine but i would touch a car ecu from another country, also some ECUs are linked via vin/chasiss number. if you swap one from another vehicle the whole system shuts down.
i replaced mine for under $50 last year if your in sydney try peter warren, don't go to the service department go to spare parts and they will program it for free. take the car with you.
I have never done that model but there should be marks on the pulleys that line up with marks on the block, get these lined up fit the belt. check your book the slack should all be on one side.
they are only around $300 supplied and fitted any towbar place. if you get a secondhand one make sure you inspect it before purchase as it may have been in a crash and been damaged.
The handbook only shows how to re sync the remote, if you got it from a toyota dealer they should do it for free. otherwise i think it is turn the key on and off 3 times leaving on then push the button on the remote, pretty sure but don't quote me.