I thought it was obvious Rey’s Luke’s daughter by the end… Her going to him and their meeting— it’s a pretty clear reveal, with her about to burst into tears at the realization she’s standing before her father. And if that’s not enough, the first teaser for the film had Luke’s voiceover from Return of the Jedi: “The Force is strong in my family. I have it. my father has it, my sister has it…” and Rey is shown. So we can conclude “…and my daughter has it.”
This is Disney, they're not going to complicate things. If they want to introduce Obi-wan's long-lost daughter, they'll do it in one of the Anthology spin-offs they're churning out annually like clockwork-- so you'll need to pay separately to see that story.