predator urine should work well to keep animals from eating your plants, but won't work after it rains. I would also add dog/cat/human hair (not your own) to help with that as well.

Water. If it doesn't rain for a month, your plants will suffer, but if you get enough rain, giving them nutes once a month will be just fine (not optimal, but fine). Just don't try and over do the nutes b/c you can't feed them ofter, less is better than more. I would get the plots ready asap and put a lot of organic matter in your holes so that when you plant, you will have lots of slow release nutrients for your plants throughout the season. Avoid fish or blood meals so that predators won't dig up your soil.

I would just amend what soil you have there this year, as it probably won't be optimal anyway, save some labor. Put some kind of mulch around your plants (as natural looking as possible) to keep other plants from growing around it and to conserve water. But if it is going to make it hard to conceal, forget about it, safety first. Good luck man