lynz-bee
1- I have a previous model year but I have had an engine coolant temp sensor issue for a long time. For my 06 version there are actually 2 engine coolant temp sensors that report to the ECU. The primary (rear of the engine block) reports to the ECU, the second unit (at the water pump/thermostat neck) appears to report primarily to the temp gauge in the dash. I have had intermittent engine temp gauge reporting in the dash for some time.
2- I would suggest a low cost (less than $50) OBDII code reader. Has been very helpful in troubleshooting my issues as well as family members with a nuisance "Check Engine Lamp" for very minor things.
3- Can't really say but if the wheel bearings need attention, that is a bit more than many home mechanics would be up to. Do make sure it's not just the tires first. You know, look at the tread, verify tire air pressures and lug nuts...

As far as the rear window, search for problems with the rear window regulator before assuming the motor is the issue.