It's an excellent film, although its depiction of history is borderline propaganda. As a work of fiction, it's only real flaw is the WAY overlong ending. Kevin Costner's lecturing becomes tedious fairly quickly.
I'd argue the vast majority of the movie is fabricated.
Since you opened the can of worms...I find there to be more logic in this movie than any of the BS I was taught in history class. While this is undoubtedly a work of fiction, many falsehoods need to be viewed within proper context. Stone and co. were writing/creating a film: details/plot points needed to be arranged so the script worked and certain aspects had to be ignored for running time's sake (possibly the mafia's influence, to name one) and composite characters were obviously a necessity too.This movie hasn't affected my opinion of what I think probably happened one way or another. It's great entertainment that I assume has caused many people to investigate (or at least take an interest in) what happened that day.
I find there to be more logic in this movie than any of the BS I was taught in history class.
I don't have any idea what really happened, and don't pretend to know, unlike you.