My take:
1) Yes I believe the intent for CFs is to mirror spells: The CF happens, and THEN you suffer fading. If it knocks you out or kills you, the CF still happened.
2) Since CFs have AR, and the targets of your CFs have Matrix Defense Ratings, I'd compare AR vs DR any time the target is rolling to resist.
3) There's no benefit I can think of in nerfing your own stats, and the CF says it is opposed by Willpower + Firewall. "Obviously", you cast it on other targets?
4) You can pay close attention to the opposing dice pools. Of course, if you have the Cleaner CF, knowing your OS really isn't important. Anytime you think it's getting "kind of high", just reduce it some.