If the OZ bikes have an immobilizer, you're limited in ECU choices as they will have to come with the red master key (or other locks and keys if you want all the locks the same). They won't be cheap. FYI, Ivan can do immobilizer ECU's.... you'll have to contact him....
Meanwhile to mitigate some of your snatchy throttle issues.... do the throttle spring unwind if not already done, reduce throttle freeplay to near zero, up the idle speed to 1100 minimum, get a G2 throttle tamer or modify the cam profile on the throttle tube to a slower rate of pull.
What is happening is when you throttle off to zero, that cuts the fuel supply and when opening the throttle, there is a slight delay as the injectors re-wet the cylinders...... depends on the situation but if you can slightly throttle back on that re-wet will occur and you can carry on..... there is no cure for this except a flash to eliminate the fuel cut, which Ivan does.
The other thing we did was install Power Commanders to add a little more fuel in the lower throttle openings. All in, we spent more than the Ivan flash costs and didn't cure it.