Okay so first off, the YT videos aren't really going to help for this car, unplugging a sensor should not affect the idle. That might be the case for newer OBDII cars but not so much with these relics. Standard idle should be 850-950 RPM. Check for vacuum leaks/other issues before attempting to adjust idle, particularly if it idled properly before.
I would recommend attempting to pull codes from the car, you need to jumper a plug under the hood and then count the flashes on the check engine light when you turn the key to run. This can be done with a paperclip.
Start there, see what the ECU might have to say about things.
It certainly does sound like you have a vacuum or boost leak, that may or may not be related to the new bypass valve. Any leaks behind the VAF meter will cause it to run very poorly. Vacuum line disconnected, split intercooler hose, etc. If you have access to a smoke machine or other method of leak testing that would be helpful.
Regarding the fan:
There are three temperature sensors on the engine. One for the ECU, one for the dash, one that controls the fan. The one that controls the fan is on the t-stat housing. Disconnecting it should immediately turn on the fan. Be wary of running the fan non-stop: I did this on one of my capris and it blew the fuse, leading to an overheat condition. 400 miles from home. That was an exciting weekend
Do you have access to a timing light? It would be good to verify that the static timing advance (done by rotating the distributor) is within spec. This could cause trouble with idle. Did you change this while changing the bypass valve?