Hi!! I'm finally answering this after 5 months, so sorry for the wait!
1. I think either way is perfectly valid. When I was personally playing the game, I'm pretty sure it was usually before rolling, but we probably made a few exceptions. It all depends on how unforgiving you want the game to feel.
2. Yes! Conditions should affect destructive moves. If they didn't, then you could end up with a character that just doesn't interact with that system anymore.
3. Sorry, I'm not sure what you mean by this.