Before I say anything I want to point out that I know the movies are non-canon and exist in their own timeline with most of them taking place during points in the story that would have been impossible to happen the way they did in the movies. Many people have analyzed where they could possibly fit in the timeline and even some tried to re-write them fan-fic style. So, now I want to take a try at it. Not wanting to create a whole new timeline, I will try to have events lead to the same destination. How much do I need to change the movies or main story to make them fit? Click "read more" and let's find out.
I am going to categorize every movie into one of 3 groups;
Easy Fit - Movies that need little to no changes to fit into the timeline.
Minor Changes - Movies that need noticeable but doable changes in order to fit
Complete Overhaul - Movies that cannot possibly fit into the main timeline and need to have major changes to both the movie and series in order to work.
Getting the obvious out of the way, History of Trunks, Bardock the Father of Goku, Battle of Gods, and Resurrection F have already been re-worked into the main story. Dragon Ball Super Broly and Super Heroes are already canon. Moving on!
DeadZone - Easy Fit
Animation style matches more Dragon Ball than Dragon Ball Z, plus Goku using the Power Pole and Kami joining in on the fight also make it fitting for the timeframe.