Star Wars concept artist Ian McCaig teased some VIII knowledge:
But here’s where it gets interesting… The meat really came at his mention of Rey, and then her mysterious background. He spoke of how Qui-Gon and Shmi had a romantic affair in early-mid drafts of TPM, and how you can still see the remnants of this idea in the final film. He also teased that (paraphrasing) ‘though none of these prequel-related concepts were able to be used outright, these ideas remain in the Lucas ecosystem, and filter through.’ AND, though he spoke thus quietly, he almost certainly then said: “…And now we have a new Skywalker.”