Questions about rules for penalties

I have two questions from yesterday's Rangers/Panthers game regarding delayed penalties.

1. There was a delayed penalty for high sticking that upon review showed that it wasn't a penalty. What would have happened if the Rangers would have scored on the delayed call since they pulled their goaltender for a 6 on 5 that shouldn't have been? I don't recall them putting time back on the clock after the review so it seemed like the Rangers got a brief man advantage.

2. When Trouba took the two minor penalties, why was it a double minor and not a two-minute 5 on 3? If another player had committed one of the two penalties would it have been a 5 on 3 for two minutes? I understand calling a double minor when the player commits the penalties in the same sequence but the second one was on a delayed penalty, far apart in time, and on a completely different sequence, so I was confused.

Thanks in advance.