Without spoiling anything, Intermission (Yuffie's DLC) takes place in the middle of the Remake storyline and basically follows what she's up to before presumably joining the party in Rebirth.
I like Yuffie as a character, so I enjoyed playing the DLC. But you could probably find a Twitch stream or no commentary Youtube playthrough to catch up on the story if you don't want to play it and not miss out.
Oh it does make sense storywise. I'm more salty about the fact that Remake + Intergrade are now free if you pre-order Rebirth. I spent €100 on that man T_T
I'm usually a patientgamer, but the call of ULTRA HD Sephiroth and Tifa were too strong for me.