I’m with DominicCobb and EyeShotFirst. Some of you all are still stuck in the pre-TLJ era with TFA. Yes, many of us, including me, were thinking everyone in the film really knew who Rey was. Her being a former student of Luke was the strongest extrapolation I could get from it. However, post-TLJ, literally everything still works. You think Maz asking Han, “Who’s the girl?” would be asked if Rey was a “somebody”? No, Maz didn’t know who Rey was, hence the question. Han most likely confirmed that Rey was just some random girl from “nowhere” (Jakku).
And also, some of you think, “Well, why did TFA give us so many hints? We were SUPPOSED to think Rey was important!” Okay, you’re right to an extent. Yes, TFA made you think with its many hints. BUT! Can you imagine how damn boring it would be if we had a twist where Rey is revealed to be related to someone we already know? Think about it. Just about 80-90% of us were thinking Rey was a daughter of x, y, or z. The BIG twist was finding out she’s just some girl that came from no one noteworthy. That’s way more satisfying than shrinking the galaxy to some lineage of heroes we already knew.

When it comes to the dynamic between TFA and TLJ, you just need to re-frame how you see those lines now. It’s called a perspective change, and it totally works. Junk scavenger girl is causing a huge disturbance in the Force, and that makes all the important people raise an eyebrow, and that’s all there is to it!