The more I think about this whole Back to the Future thing the better it gets.
We do have multiple time travel books that could be used including A Connecticut Yankee in King Arthur’s Court. To write the book he would have had to go “back.”
We have lots of little robots in Gold’s store…definately a “future” thing.
We have the Enchantment Under the Sea dance where Marty sings on stage. When Emma was on stage and Henry in the audience (for the debate) huge fish props are in the background. In the Under the Sea scene we have dolphins on the banner…in Desperate Souls we have dolphins on the banners…not cartoonish but rather more like the sea horses in the Marty on stage scene.
We have microphones in Neal’s apartment similar to the one Marty used…
Since I haven’t looked for this connection these are the first things that come to my mind…it will be fun looking for more. Please post if you find some. Even if this theory is wrong…this could be a lot of fun.