From what I've read the KK holds its moisture well you may not need the water pan but if you want i don't see any problem sitting it on a rack below . As for temp you are correct but with a kamado it takes a while to heat soak so in the first 1/2 hr to 1 hr you can bring your temp back down easily this is great for searing a steak first and then finishing off .hope this helps I'm sure the resident baker will chime in with even better advice
Outback Kamado Bar and Grill♨