You will need to use an AE82 bigport ECU anyway which I think incorporates the idle up. Someone will know.
But yes, get it running then worry about it later. If you are serious though, you will save yourself a lot of angst and just source the proper AE86 looms - all three of them. The loom to the rear of the car isn't an issue as you only add one wire.
But you can do that later. I drove mine without it for about 7 years before taking it off the road and doing it properly.
