Yes it can hurt your engine to drive with a bad knock sensor. The knock sensor should be replaced as soon as possible.
Yes.
At highway speeds, YES!
That is the CMP or Camshaft Position Sensor. Driving it can and possible WILL hurt the engine eventually. The Squeaking is caused by the gear train being worn out. The CMP in this engine is tied into the oil pump for the vehicle. If the CMP Geartrain was to fail or seize (the reason why its beginning to squeak.) it will stop the oil pump and no oil will be fed to the vehicle. The danger is here, that on this vehicle when the Oil Warning Light comes on, the engine is usually damaged beyond repair. See Related question on how to change your CMP
Yes, you can do serious damage to the engine if the converter is clogged.
it adds a lot of strain on the engine especially if the drive train is directly under the engine. (front engine fwd, or mid engine rwd)
No. Your engine will turn more RPMS and your gas mileage will not be as good.
No it won't hurt the engine BUT you could get carbon monoxide in the car. Don't sit in a parked car with the engine running if your exhaust is bad - it could kill you.
It won't hurt the engine but it will hurt the catalytic converter.
Overdrive keeps your engine RPMs low when you drive faster than 45 mph Its there for fuel economy If you drive without OD it doesnt hurt anything at all except your gas mileage
Yes it will hurt and hurt severely. White smoke is almost always a sign of a blown head gasket or cracked head. Coolant is entering the combustion chamber and is also entering the oil system. You will destroy this engine if you continue to drive it in this condition.
Yes if its big hail stones it could probably knock you out.
Yes, it will not hurt the engine but you will more than likely get a ticket for loud noise.