Airbag control module. Disconnect battery leads, wait 10-15 minutes, unplug and remove this module. Keep it carefully, install back in last.

Yes. Just look for clutch from turbo car of any displacement. For example, Sachs 3000 693 001.

Increased boost pressure is not so dangerous for rods, as an EARLY boost engaging. ECU controlling boost depending of rpm and throttle angle. Just look at those two boost maps. 1st is stock, M4.3, 225 bhp. 2nd is tuned, 300 bhp declared. I've tested it. Runs much better than stock, but I didn't feel...

Let the engine get warm at idle and turn on the heater (yes, and don't look at 90F outside). If you get HOT air, then water pump is OK and thermostat is the prime suspect. But not the only.

I would leave it as is. There is no mechanical load, no oil or gas pressure. Less than 15% of bearing area.

My way to hold any pulley in any direction using an old belt
Free end of a belt should be placed at any strong part of engine

Cylinder block is a sandwich type

Just remove drive shafts, radiator fan and battery mount. You will have enough space to remove the engine in assembly. Wheeled dollies will be useful too.

Bolts checking for stretching, need 2 same (cylinder head bolts on the photos as an example).
Bolts at 1st pic can be re-used, at 2nd pic are for garden trolley only.

Try to exchange wheels. Left and right, if they aren't directional, or rear and front. Defective tire can pull the car aside, even if it looks good.