1. It can be done, if you're a good mechanic. I don't even know where to begin to point you for directions, however. Not what you want to hear, but it would be much easier to just buy a car with A/C.
2. Back fender? Not replaceable like the fronts, unless you cut and weld.
http://car-part.com/ is a great site for searching junk-yards all over the country, including your home state.
3-5. Someone else will have to handle these questions.
Sorry I couldn't be of more help.