Ok everyone, theory time!
A few posts ago, I asked about who could be SC1, 2 and 3 before Roche.
Now, after rewatching Nibelheim chapter, I notice this part in Shinra mansion.
The obvious foreshadowing is that this hints Hojo's experiments on Cloud. But wait, there's more. If we go to Shinra Manor basement, we'll see a lot of Vincent's writing on the wall, one of them is this.
Source
These are formulas by Vincent to serve his plan to destroy Hojo. And we know that emo grandpa hadn't left that basement for decades, so he can only have access to whatever is available in Shinra manor, including those 3 S cell tubes. And somehow, he can make connection to Jenova, Loz and Yazo.
Future knowledge? Sure, maybe, might as well. But that's basic af. I want to propose this theory instead.
SC1, SC2 and SC3 are not Cloud, Zack and some unknown poor dude. No, they're the bases that later will become Loz, Yazoo and Kadaj.
Consider how many side contents of Nibelheim revolve around Hojo's lab rats: Roche becomes robed man, Broden becomes robed man, Chadley turns out to be a real boy. This could be a great way to hint at a different origin of the Remnant triplet that connects to Sephiroth even more directly.
