You asked about wiring.
The escalating issue is that the throttle bodies are different, and so are the sensors on the throttle bodies.
"Okay," you're thinking, "I just swap the throttle body." True -- except that one uses a 3-bolt base and the other uses a 4-bolt base. And the heads were redesigned in 1991 to raise the ports, so it isn't as simple as just swapping the manifold -- without some modification, the ports won't line up. The most foolproof solutution would, indeed, be to use just the 92 block and swap the 90 head and manifolds onto it. However, while that will keep everything closest to stock (which makes future maintenance easier in terms of diagnosis, especially if someone else is doing the work), you won't be taking advantage of the better flowing head on the 92 engine.
I have not done a hybrid swap such as you are contemplating. Your choices are to (1) swap over the 90 head and manifold and throttle body onto the 92 block; (2) keep the 92 head and try to adapt the 90 intake manifold and throttle body to it; and (3) keep the 92 head and manifold and adapt the throttle body. I don't know enough to advise you which way is easiest or "best."