I'll agree in some ways. For Ray, I think that if she's related to anyone it'll -have- to be luke or Leia. No other bloodline was stronger in the force. And with finn, I hope he isn't lando's kid. That'd be too obvious.
Well, yes. Mostly because I think it'd be stupid that they'd be related. It's not like they're ALL related to eachother. It's like asking one British minecraft friend if they know another one that lives on the opposite side of the U.K.
Well it's likely Ray is Luke's daughter, cause at the end of the movie he was standing next to a grave (his wife?) but they may also do they twins separated at birth thing (with Ray and Ben: Kylo Ren)
That didn';t look like a grave to me. If they follow the proper lore, the first jedi temple will be on Tython. If luke is searching for it, he could have been, at that time, at the ruins of another temple. That could be grave pile, but probably not for his wife IF Rey even is luke's daughter.