Luckily, we've never been parade people, so we don't have to deal with the kind of people mentioned by the OP. We do the fireworks, but do the Dessert Party, which also helps to avoid these people. We had incidences like this multiple times our first trip in 2004 and have made sure to never take part in large group activities again. There are just some people who either don't care about how they affect other people's enjoyment of their vacation, or even some who seem to enjoy causing problems. Hopefully you don't have these experiences again. Other than that, it sounds like it was a great trip.
Aside from the few experiences, it was a great trip! I am definitely going to do the dessert party next trip, I don't want a repeat of what happened next time. I'll also probably steer clear of the first MSEP of the night and attend the second (if there are two).
I'll probably do the dining package again for Fantasmic!, but unless Disney does something to resolve the mass horde of people on both the FP+ and standby sides of the entrance, I'm going to avoid entering the amphitheater until it's all clear.

