Do the events of the Dragon Ball movies happen to some extent in the series?
Besides the dragonball super movies everything else in Z is considered non cannon as in it had nothing to do with the actual series. I don't think toriyama was involved in any of the Z movies so they are kind of fanfiction by other authors. 

An easy rule to follow is anything that did not happened in the manga is not considered to be a part of the series. If you take the a look a latest super manga you will see similarities with the last two movies so they are considered to be cannon.