I live in Florida, so it's mostly UV light that I have to worry about, not snow and ice. That being said I've been using a regular sprinkler valve outside for years without much trouble.
Overall I had to buy three different parts from the local home improvement store, lowes in my case, but home depot may have everything you would need as well. The 3/4 threaded valve which came with two adapters which I didn't end up using. The male hose adapter and the female hose adapter. I remember that all three were in the same aisle, but don't remember the part numbers off top of my head. If I do get around to searching them out, I'll update the post, but I think it may be easier to just go looking for them at the store, or ask associate. From what I do remember, I think you should be looking for "3/4 mip" adapters to fit the valve.
To answer your second question, as long as none of your 13 primary zones leak, having the master valve active during your 14th zone irrigation should not present any issues.