So far, when it comes to The Force Awakens and quite literally in the case of The Last Jedi, clues to Star Wars titles are always hidden in the opening crawl, of which Rogue One and Solo totally ditched.
The Force Awakens title was delivered well in advance of the first teaser, as was The Last Jedi.
The title The Last Jedi was also pulled from Snoke dialogue, but was included in the opening crawl as well.
The backstory on The Knights of Ren hasn’t yet been revealed, and their history is still up for question.