Okay, I'm taking the bullet and watching the vid.
-Ray doesn't realize that Nomura pointed out the helicopter trio will be named characters with their own content, so he actually has more of an incentive to theorize than he thinks
-Surface level, what if blond guy is Cloud's dad?
-Going deeper, what if Cloud's dad wasn't his biological dad? He has a mom, but he was the result of Shinra trying to reproduce the process that made Sephiroth using blondie's sperm in the way Hojo's sperm were presumably used for Sephiroth
-Nibelheim is a very X-files-esque Truman Show type horror show even before Cloud's birth, after Shinra presumably wrested it from the Junon Republic. So, even before Sephiroth burned it down, it was already inhabited by Shinra employees acting at being residents
-Cloud will uncover more about this stuff when he visits Nibelheim, not just the Sephiroth Copy experiment evidence
-This serves as part of the new basis for Cloud's identity crisis. Jenovaroth points it out and Vincent seems to know about it because the experiment would have been ongoing when he was a Turk (although that doesn't actually line up chronologically)
-This would explain how Cloud had the strength to send Sephiroth into the Lifestream
There's a million things I find farfetched about this theory, but if I had to choose one it's the needless layering of gotcha genetic experiments. Everyone and their mother has wondered at some point whether there was something special about Cloud that allowed him to counter Sephiroth in the reactor, but most people over time come to agree that Cloud's relative mediocrity is pivotal to who he is as a character. Adding some weird superhuman backstory would completely dismantle that and jeopardize what fans love about him and his narrative arc.