you could if you know how todo it you would have to do it carefully so you dont poison your self.
No
yes
It is possible that the coolant mixture is not correct- that can make a car run hot. It is possible for the water pump to go out. Also it is possible to be having a problem with the radiator fan.
Refrigerant - not coolant - and no, they are not compatible.
Do not have your car on. First step is to make sure your car has enough engine coolant, if you are low, buy some at the store and put it in its proper place for your car(If you do not know where that is then consult your owner's manual for engine or engine coolant.) If that is not the problem, then it is possible that you have a leak somewhere from the coolant container to your engine. Either check for any possible holes or loose connections or take it into an auto repair shop.
drive it without coolant
( YES ) you can buy premixed engine coolant ( antifreeze mixed with water ) or concentrated antifreeze
Yes
Yes, the signal to the PCM can be wrongfully perceived as low coolant, even if the car is full of anti-freeze.
Coolant loss out of what? Car, home air conditioner? Please add additional details in order to receive an answer.
It is possible to put water only in the reservoir for coolant on a car. However, this should only be a temporary fix until it can be repaired by a mechanic.
Low coolant level and possible coolant leak.