1 and 2: Not always, depending on the exposure used taking the pictures. ACR is good in highlight recovery. If there is anything left in the original file ACR will get it back ( and maybe you can try to buy the book Real World Camera RAW, written by Bruce Fraser and Jeff Schewe - the latest version is almost out I believe)
3: in ACR 4.2 try to correct both highlight and shadow using a combination of the exposure, recovery and fill light sliders, but don't overdo with this options, just keep an eye on the screen and the histogram.
You can also use the other sliders in the exposure window of ACR.
As always, there are more ways to achieve results, personally I rarely use curves but others enjoy them more then the easy exposure sliders :-)