Skywalker Family - I am personally still not 100% convinced that Rey isn't a Skywalker of some sort. I think it's still entirely possible that Kylo and Snoke were lying to her. I get that there's a lot of suggestion that Rey and Kylo have a thing going on there, but it's no more suggestive than things were for Luke and Leia in Empire. I still think it's entirely possible that they're siblings or cousins. Even if they aren't related, I still think there's a lot of room for Rey to take the last name of Skywalker either by ending up with a redeemed Ben, or just adopting the name in general to carry it on in honor of her adopted family.
If this were another series, I'd suggest they just have her and Ben do the bow-chick-a-wow-wow in Act II, have Rey kill him in Act III, and then pop out a brand-new Skywalker 9 months later.