1) 1-5 minutes. If you're 2 wks or so out from a meet, you can limit to 1-2 minutes for some conditioning. But basically you want to be as recovered as possible for each rep. This is neurological training--rushing is counterproductive.
2) 20/10 is arbitrary. Do what works for you. Personally I can do a lot of snatches, but CJs take the starch out of my britches quickly. So I take smaller jumps in the snatch and bigger in the CJ. It's going to depend on how much you're lifting, where in a cycle you are, etc. If you're snatching 60% and CJing 95%, you're probably not going to be doing twice as many CJs than snatches. Again, experiment and see what works for you.
3) Very commn to have one day be focused on a single lift. So a snatch day may literally be only snatches, or it may be snatch-related exercises like snatch balance, muscle snatch, OHS, etc. Again, whether or not you do this depends on a lot of things. Another thing you can do is have a focus day but still do the other lift light and low volume. So snatch heavy, CH light and only a few singles one day, then the opposite another day. See number 2 regarding experimentation.
4) When doing multiple reps, yes, reset for each. The point is quality repetition, not just repetition. It's not aerobics class. Don't rest too long--just long enough to set up each rep as you need to.