Ok, so this question (probably again) What is the deal with Tifa and Cloud?

Alrighty, these might be spoilers, so leave now if you don't want that (as pointless as this is, saying it as the tradition anyways).

So was Tifa pretending to know Cloud from youth? Or was the clone issue just a lie or mistake from Hojo and Cloud was "real"? Or was Cloud "real" and was just screwed up or infused with "sephirothness"? If he was a clone, how did he get fake memories exactly, and why of the "real" Cloud? And if that's true, why did Tifa pretend and play along when he had mistaken memories? Or was she the one mentally unstable, or screwed up in the same way as Cloud? Somewhere it's mentioned that the clone came to have such memories because they were from Tifa. Is that true, if so how and why? It was times like those that I started to think Tifa was the clone, or "non-real" one. it's even said she didn't have family.

I've seen many answers before that are certain one way or another, but there is nothing clear, and no proof. That's how it's meant to be right? Unclear. Or did I miss something?