The pinouts are the same for all OBD2a (96-98) Honda ECUs, so if the stock OBD2a ECU ran the engine, all grounds, etc., are where they should be. That's why I'm saying you have another problem. If your ECU harness is OBD2a, and the ECU is OBD2a, which means that the ECU harness plugs right into the ECU, then you have all the grounds that you need and your problem is elsewhere.

What crank sensor into the distributor? You have two crank sensor inputs on the OBD2 ECU, so you're saying you already bypassed the crank fluctuation sensor input to the ECU by splicing it into the crank sensor in the distributor?

The OBD1 ECUs don't look for a crank fluctuation sensor.

I don't know what else the problem could be without visibly giving a CEL.

Does the H22 ECU have an immobilizer board inside? I can't remember when they started doing that, but I don't think it was nearly that early, and it wasn't in all models anyway.