Hi there.

1. Nope, no driver required. Your driver is the C&Q driver.
2. Yep, at least as long as you re-enable C&Q in the BIOS menu and select a powersaving profile in control panel -> energy options (or the like). You need the AMD driver for that to work.
3. Almost - it's the complete CPU usage, including kernel time (time spent in OS kernel mode).
4. I haven't taken a look at the mod yet, and probably never will, therefore I can't help you. The labels seem to be rather crappy though, I wouldn't understand it myself.