I think you’re probably fine with the blu-rays. When in doubt, the current official release is a good rule of thumb. Especially since it’s looking more and more like they’ll just ride out the 2011 discs until they do a 4K release rather than putting out a remastered SE in the meantime.
This is why all signs point to 2020.
Since the new format only just launched last year, they weren’t going to release a catalogue title as big as Star Wars until several years in anyway. But that will only be an added bonus to the fact that 2020 is when they completely get the rights back to Empire, Jedi, and the prequels.
But the other factor might be whenever they choose to go on hiatus:
“There seems to be a plan for a hiatus on Star Wars movies – a plan that will happen after a few years after the end of the Sequel Trilogy.”
Now, the way that’s worded, does it mean “several years after the end of the sequel trilogy” or does it mean “several years from now, which will be after the end of the sequel trilogy”?
They don’t want the grand debut of Star Wars on a new format distracting from the latest new Star Wars movie or the home video release thereof. That’s why I don’t see anything happening over the next couple years other than reissues of the 2011 discs. If 2020 and 2021 still hold new Star Wars movies, I could only see the 4k release happening within that stretch if a long-enough window presents itself. For example, if they move back to December for the 2020 movie it would give them a year and a half between movies and they could put out the 4k OT in the Fall of 2020.