Aircon rad can be removed by taking the slam panel off. You will also need a looong extension to get the two bottom bolts through the bumper.
Should be fine without the aircon rad in as the compressor clutch shouldn't engage.
If nothing else, you can try it and if it solves the overheating then you will know what the problem is.
On the viscous fan, it never completely disengages, insofar as it will always turn.
However, the amount of torque transferred from the engine to the actual fan will be almost nothing when cold, a bit more when normal and close to fully locked when it's getting hot.