Well, I guess we agree to disagree on what Neil would have done. I ageee he loved and proteceted Gotti but he was still known as a keeper of omerta and the traditions of 'the life'.
I agreed he stalled Big Paul but I don't recall reading anywhere where Neil heard the tapes. If Neil had heard the tapes I would agree but if he hadn't he would see that Gotti would be dead and I don't think he would kill Paul over that. He was a follower of the old ways. That's why he didn't kill Paul when he was passed over as boss. He told Gotti that that was what Carlo wanted and he had to comply.
Killing a boss was still outlawed and he would have to get commission okay like Gotti did directly or indirectly, with the exception being the Chin who was close to Paul and followed the rules about killing bosses.
None of us really knows what Neil would have done but I vote for whacking Gotti if he was ordered, especially after hearing the tapes and it was about drugs. Outlawed by the commision. Plus, it reflected badly on his leadership of the crew since he let it go on.
Neil knew part of the life was sometimes asked to kill a friend. They all know that the best way to get to someone was to have their freind, who the victim would least expect set it up. I'm sure Neil has done his fair share.