What are the specific points of contention that JJ and Kathleen had?
Maybe someone with more knowledge of this can speak to it, but there were rumors swirling during pre-production that JJ was going to leave the project because he and LFL weren’t seeing eye to eye.
As far as I know this had to do with the release date.
I’d be very interested to read a history of the production of Rogue One whenever LFL is willing to release that info. I’m not sure I completely buy the general idea of what caused the reshoots - LFL/Disney didn’t like that the movie was too weird or too un-Star Warsy or whatever so they hired Gilroy to replace Edwards. I think, more likely than not, the film simply wasn’t good, and Edwards knew it as much as Kennedy or anyone else. A lot of the changes were deep seeded character and plot things, so it’s probable that the main issue pre-reshoots was that the story wasn’t tracking. Edwards has worked with Gilroy on reshoots before so I think that was very much a collaborative process, and I’m pretty sure the only reason Gilroy directed anything at all was because Edwards simply didn’t have the time to direct all the reshoot material by himself. Now, is it possible that there was an attempt to make things “more Star Warsy”? Sure and I wouldn’t be surprised if that’s why Desplat left, for instance. But I don’t think that was the primary goal and I don’t think it was really “made by a committee” other than the fact that a bunch of people sat down in a room and thought “how can we fix this story?”