It wasn’t the sequel trilogy, it was Abrams’ and Terrio’s final script, and even that was instigated by Carrie’s death. Everything else has been pretty well planned out (even if fans didn’t like the plans or didn’t guess everything prior to a release).
Yeah, Trevorrow’s initial script for TROS was written more than a year before the release of TLJ, and the same applies to TLJ as well. Watching the first two movies and then reading Trevorrow’s first draft, there’s a clear through-line in the entire trilogy. It’s just that Carrie Fisher’s death threw a spanner in the works.
As for lightsaber colors, things that small just don’t matter in future instalments. A story decision in Clone Wars (to further visualise Ahsoka’s and Anakin’s relationship) superseded the previous description of events with the green sabers. Time that isn’t expressed on screen or in prominent prose shifts (a timeline on wookiepedia is not more relevant than the media it’s describing, for example).
Also, a lot of these details won’t be revisited, especially not right away. They aren’t gonna do a prequel that goes to Kef Bir any time soon, and there’s no current reason to revisit the planet any time soon.
So, be more casual with the canon. Creators are. Canon is only important until it gets in the way of story.
That’s completely true. Canon has never been really important, and only the most egregious instances of self-contradiction really bother me. In the end, it’s just a fictional story.