Not getting into all the stuff about things that were in the books and comics that should have been on the big screen, but I can't help but feel her location on Jakku will end up being relevant. It was the focus of the Aftermath trilogy (from the Imperial side of the story), and Chuck wouldn't have just pulled all those connections out of his butt -- he worked with what the Story Group gave him. Niima Outpost in TFA is named after Niima the Hutt, who used to have that part of Jakku as her turf during and before the Galactic Civil War. Hidden underground in that area was one of Palpatine's Observatories that he'd begun establishing while he was still Chancellor.
We've only seen a couple in the new ancillary material, and they didn't all serve the same purpose, but they all were called that because, whatever else they did, they all looked outward to the Unknown Regions. Palpatine felt a pull from outside known space, speculated that it might be the source of his power in the Dark Side, sensed there may be some "dark presence" lurking out there, and part of Thrawn's mission to the Unkown Regions was to accumulate navigational and scan data for Palpatine's observatories.
The one on Jakku was the one he purposed for the Contingency. In addition to other elements of that plan that went into action elsewhere, this location housed a replica of his staryacht Imperialis (which Phasma would later scavenge hull plating from to make her armor) and ancient computers from some other civilization containing maps of the Unknown Regions and ongoingly using the data that Thrawn and a series of dispatched probe droids had gathered to chart potential routes ever deeper into that part of the galaxy. Whatever else, this was where the building blocks of the First Order were being gradually accumulated.
There was a borehole to Jakku's core that was meant to be used to destroy the planet and the Rebel and Imperial ships that were to have been lured to battle over it, but that part of the Contingency got foiled. There was also a storehouse of Sith relics and artifacts there, but Palpatine seems to have stashed those everywhere.
Until things potentially play out otherwise, I can't believe Rey -- the only human to have lived in proximity to that place since Grand Admiral Rae Sloane, General Brendol Hux and his son Armitage, and their cadre of child recruits all fled in that Imperialis (each Observatory had one) -- just happens to be the focus of whatever this awakening of the Force is, with no connection between the two. With Palpatine returning in some form, that makes me suspect her home for a decade is no coincidence.
Does every friggen' thing in this saga have to connect to everything else? Phasma couldn't just order custom armor through the supply chain?
