1: easy, takes 40 mins with a shop manual and no prior experience on the V8s
2: clutch or brakes?
if its the brakes, you may need to rebuild your calipers, or check the grommets connecting to the reservoir
3: set aside a couple of days for that, and do the intake manifold gaskets while you are at it.
4: it pumps coolant through the block to the radiator to cool the engine.
they are known to fail when the plastic impeller shatters like an old saltine.
get a rebuilt one with a metal impeller and some new hoses and thermostat.
5: there is no 5, but you should get the Bentley shop manual, and also spend a few days reading through prior posts. most of your questions will be answered, although you will have a lot more when you are done.