..is anyone yet to consider that
She may not have a 'family'?
Remember the immaculate conception of Anakin Skywalker's birth? he had no father, he was a being born purely of the force, and of the love of his mother.
Whilst it stands to reason that Rey must have a mother in order to be born, the hunt for who her father is may be a deliberate misdirection. In an age where the First Order are leading a crusade to find and destroy any remaining Jedi and Jedi Artefacts, it would also explain why whoever was her 'family' abandoned her on a distant planet, to hide her from 'herself', as it were.
Personal theory, purely conjecture and just to throw the cat among the pigeons:
Kylo Ren, being the grandson of Anakin Skywalker, has been raised with the notion of 'Destiny' surrounding his lineage. As Anakin didn't bring balance to the force, and (possibly) neither did Luke, he comes to believe that he is the destined 'Chosen One'.
He is the Star Pupil of Luke's Jedi Academy as a result of this: until, whilst Kylo is still a prepubescent, another of Luke's students (which, sure, could be revealed to be Jyn Erso for the sake of neatness) produces an immaculate baby alá Shmi Skywalker: this is kept relatively hush hush, for the childs protection
Over the next few years the attention shifts towards this new child: until eventually, as a moody older teenager, Kylo Ren basically rampages, and begins to massacre the younglings of the Jedi Academy indiscriminately to eradicate the 'chosen one', in a reference of Anakin's Jedi Temple attack on Coruscant.
Rey is hidden away on another planet, and as in the Obi-Wan tradition appointed a guardian to look over her: possibly Lor San Tekka, who is possibly portrayed in his younger years by Mads Mikkelson in Rogue One.
Considering the 8 Years between actors, and allowing for generosity, we see Rey is about 5-6 when she is 'abandoned' on Jakku. If Kylo Ren is circa 10-12 years older, this would put him about 16-18 when he turns to the dark side.
Skywalker goes into hiding, one of the only remaining people who knows whether Kylo Ren killed the correct child or not, and largely ashamed that he repeated Obi-Wan's mistake of not realising his pupil was being corrupted by the dark side.
Some of the minor details (like Lor San Tekka and Jyn Erso) are long shots and are an attempt to enact a cyclic narrative, but apart from those elements, anyone have anything concrete that completely eliminates this theory?