Considering how Kylo was all "WHAT GIRL?!?!? *chokes*" about Rey with Mitaka, I'm pretty sure they have some serious backstory, like she was a youngling that escaped the massacre at the Jedi School, with or without his help, and there's some kind of yeah, mentor impluse there now.
Re: Question about Poe's interrogation
Considering how Kylo was all "WHAT GIRL?!?!? *chokes*" about Rey with Mitaka, I'm pretty sure they have some serious backstory, like she was a youngling that escaped the massacre at the Jedi School, with or without his help, and there's some kind of yeah, mentor impluse there now.