Project H

So i bought a 1999 civic dx which has no dash or wiring harness and i was wondering what the difference in the OBD2's are cause i can find 96-98 heater cores and dash's easier and was wondering if i could use the harnesses from those years in a 99?
Also can i use the 96-98 engine harness in a 99?

94EG8

If you want to run a '96 - '98 harness and heatercore that's fine, but the engine, underdash and cabin harness all have to be '96 - '98, you can't mix and match them.