Q3-4: The CF lenses comes with more modern shutters (Prontor), which seems to be somewhat better than the older Syncro Compur shutters. Also, the ergonomics of the control rings and tabs are much better with the CF lenses. What you miss with a CF lens is the self timer, which is quite odd to operate anyway. (If you intend to use a C-lens self timer, a locking cable release seems to be the way to go.) In general, newer lenses are more expensive than older lenses. There is quite a difference in terms of money between C and CF lenses, partly because Hasselblad and some repair workshops are running out of parts for the Syncro Compur shutters. The most common cause for breakdown is storing the lens for too long time between usage. I.e. all Hasselblad lenses should be given a monthly exercise, which will keep them happy.
On the more common lenses, e.g. 80mm 150mm etc, there is very little, if any difference between a C and a CF lens in terms of optics and optical performance. I.e. once it's time to press the buttom any vintage of lens will give you excellent results.
//Björn