Well, since this is a plant that's hardy in a chinook-prone zone 3, I'd say it's not especially finicky!
Chances are that winter wet would do it no good, as a guess.
Any non-sterile plant that gets pollinated is capable of self-seeding, so the second question isn't really answerable. If a hardy plant is grown and produces seed and the seed drops on the ground (rather than getting blown or washed away or eaten by something), then it pretty much falls to chance as to how many seedlings you end up with.
