I'm playing Diamond City Blues, but reverted to an earlier save after reading some information about this quest online. Is it possible that either or both Diamond City and Goodneighbor become hostile to me after completing this quest? Also, I have both Paul Pembroke and Henry Cooke with me, but nothing happens at the drug deal. I read that I didn't have to bother to talk to them, that I would end up in a crossfire. But they won't do anything until I talk to them. Does anyone have any help/advice on this quest? Would be appreciated, thanks

Neither city will become hostile to you based on what happens in this quest.

Yup, neither one was hostile to me...I even put a bullet in each (well about 10 into Cooke for some reason)..and Paul was asking too much..
Also you will eventually get a dialogue in diamond city with Pauls cheating girl, and can tell her any of the options (I told her straight I smoked her dude), with no consequences...just don't shoot her..the guards didn't like that very much

But doesn't the father of Nelson get pissed at you in Diamond City? I read about bugs that would turn the whole of both Diamond City and Neighbour hostile on you because of this quest...?