Use your stock harness and either a 94-95 LS ECU or a 92-95 DX ECU.

-Do I NEED to get an OBDI LS alternator? Yes, any OBD1 B-series will work, if you don't have this, you can rig up a d-series to work, only the bottom will bolt in, the tension from the belt will keep it from moving
-Do I need to swap the plug that comes out of the base of the distributor on the B20 with the plug from an OBDI integra LS? will not plug in, use an OBD1 b18b dist unless you want to swap plugs
-Does the OBDI LS engine have a knock sensor? If not, will the knock sensor on my B20Z be used?no knock sensor on the b18b, LS nor DX ECU won't look for a KS
-Can I use the injectors, fuel rail, and throttle body from the B20Z? plugs *may* be different, not sure....I think it's the injector plugs that are different