For the offside discussion: I think that once an alotted amount of time passes, say 10 or 15 seconds, then the play is unreviewable for offside. Some of these offsides called back, like when a team cycles the puck for 30-45 seconds and then scores, while the play is offside if is not the reason the goal went in, it's another defensive breakdown that leads to it. And these close plays, you have to realize teams have people watching it on bigger monitors than the refs are reviewing them with, and telling the coach to challenge a play. I doubt if any coach this year challenged a play before somebody in their organization said it was close enough to risk it. I didn't see the play in question tonight, but I think there's no doubt that a video coach is watching it and tells Lindy Rush he should challenge it.
Challenging goalie interference is much more agreeable IMO. It's pretty clear when contact with a goalie interferes with his ability to stop the puck.