I think your most important task here is to identify the core theme of your epilogue. Is it that Rey is the legacy to the Jedi? Rey is the legacy to the lessons Luke learned/the force? Are we seeing what happens next to the OT main characters? How the Galaxy changed as a result of the victory in ROTJ? That a permanent victory was achieved after ROTJ? That there will always be a struggle and always be someone new to pick up the challenge? Is it all Palpatine’s story (probably not)?
What are the themes from the OT that most resonate with you? - projecting that forward into the ST, which plotlines best support and continue and conclude those themes?
Really good point, Eddie! You’re definitely right, that honing on the theme of the epilogue is crucial.
While Rey is the central POV, it will stray from Rey briefly when necessary, and I’ll try to keep most scenes where the OT characters interact. While the focus is on Rey, the story is also about the conclusion of Luke’s story. This film will retain all of his scenes from The Last Jedi. The story is basically depicting Luke’s torch being passed onto Rey, after she finally decides to take up the mantle of hero.
One of the central themes as I imagine it would basically be one of the things you said: That there will always be a struggle and always be someone new to pick up the challenge.
The prologue would show that there was war before the war of the original trilogy, and the epilogue shows that there will be war after it too. This is Star Wars, after all, but the message is that even though there may never be a war to end all wars, that doesn’t mean those fights aren’t worth fighting.
I think this idea of history repeating itself is hard to avoid when looking at the Sequel Trilogy, and honestly the way I think The Last Jedi addressed it is the only interesting answer we got from any of the sequels.