Trapping?
#2

Well you can't totally reduce the risk. You should be using bait/scent specifically for your target species. Besides leg hold traps aren't going to hurt a dog and you should be carrying a catchpole to release pissed off dogs from your traps.
#4

You don't know his location so your assuming he had to take a trappers course. I can tell you not all states require you to take a trapper education course, mine does not. So it would be ill advised to pretend that he has.