The fans dont run while the car is in motion above a certain speed. Mainly because its not necessary, the airflow from motion is normally enough, but it can be an impediment to cooling.
I wouldn't be wiring the fans to run continuously. They aren't designed to run continuously and it might cause issues with the engine temp control. Falcons typically run spot on around 93 to 95deg rain, hail or shine without any help. Interfering with that might cause you to use extra fuel.
Your problem sounds more like a blocked radiator, internally or externally, or maybe a slow thermostat. Making the car work hard when the fans are off and relying on airflow for cooling any blockage limits the cooling ability.
Temps that rise at low speeds and at idle are typically fans. Temps that rise when the car is moving, moving onto a freeway for instance, is usually a blockage in the radiator.
You recent lists of problems would be frustrating, specially if they happened in a short space. But they are part and parcel of owning an AU. I doubt there would be any AU owners who haven't experienced all of these in the course of ownership. Even back to EF/EL days. I had all those things happen in the ownership history of my EL's back in the day.
I'll admit the blend door is fun. Did a few of those in my time. Hopefully they didn't sting you too much as its not too had a job.
The difficult thing would be sourcing the parts given the age of the these cars now.
