"This was supposed to be a "friendly" game between neighbors and it's escalated into some very ill feelings."
That is a sad thing when a friendly game goes sour. I have a neighbor who wants to play but if, I repeat, ( if ), I were to beat him on his own table I would not feel right and think he would feel even worse. It has happened to me before with other friends. Plus he insists on playing for money. I don't want or need his money and the hard feelings that goes with it! Do you live in my subdivision. Just kidding.
"I'm also all for clarifying rules before play, but it is impossible to run through every situation before hand."
I agree 100%. I guess you need to ask before every shot when playing with strangers or friends. But in bar leagues, BCA certified, you can not ask a question of your opponent, team captain or team mate as that is considered coaching or unsportsmanlike conduct. And if you play Ball in Hand you have to ask before you pick up the Cue Ball or that is a foul also! You can not catch a ball going into a pocket including the Cue Ball. That rule I agree with.
The funny thing is that I just had this conversation with a straight pool buddy recently about how the game of 8 ball has changed from bad to worse; just our humble opinion. That is the reason that a group of us only play pool with each other; we're older and mellower. If playing with a stranger I will ask as many rule questions I can think of. Do your self a favor and go to the BCA official rules web site or the pool rules section here.
Print a copy and ask where it states your shot was a foul. This might, I would hope, end the bad feelings?
By the way, since getting back to playing this last October after doing other things in life, I have been wrong many times on many issues or rules and have had come back the next day to say I was wrong about a rule. I think that is what reasonable adults do.