Got the EVAP system working! Now to have 100% federally compliant emissions I just need to get the downstream O2 sensor wired up. I believe that is normally on the body harness of an RSX or TSX, while it's on the engine harness for the Insight, so that will need to be made from scratch.
Also installed a transmission brace between engine and transmission. I had a hard time finding this part, and when it arrived it was filthy.
Also had a chance to look into the temperature gauge. The sensor itself is a varistor, and the ECU measures resistance over it to determine temperature. The gauge cluster is not connected directly to the sensor though, and instead receives an analog PWM signal from the ECU over (Insight) ECU plug B15 (red/grn) "MTRTW". The RSX has a multiplexer which feeds its cluster, so I have no way to feed the Insight cluster the correct signal.
So I have two choices: 1) I write some Arduino code and see if I can figure out the signaling myself, or 2) See if any of the S2000 dashboard converters work, since its cluster is very similar.
This should be a super valuable resource should I choose to build my own converter:
https://github.com/pablobuenaposada/...-in-civic/wiki