Yeah - that ammonia test is hard to read. You should not have any ammonia in a cycled aquarium. Here is a trick - test some seawater you KNOW doesn't have ammonia in it and then your tank at the same time - see if the colors are the same (just to confuse things a bit - some brands of sea salt have 0.25 ppm ammonia in them when you first mix them, Instant Ocean is one).
Regarding your initial question - I have an answer about the mandarin quarantine - don't get one (grin). I've never been able to find a good solution to this - what we do is get a good healthy one, larger is better and put it in a non-fish coral propagation system for 45+ days. We raise live mysids and get adult brine, so we augment food with that. Another option would be to get a tank raised one (from Biota?) and just take the risk and add it to the DT right away.
For CUC, we hold them for 30 to 45 days in a non-fish system. Not a "full" fallow period, but I've never had a problem with that.
Jay