Yes, everyone eventually dissolves into the melting pot to be recycled again, but a person's consciousness only seems to dissolve when it stops resisting the assimilation. Aerith, Zack, and even President Shinra stuck around for a while.
I'm just wondering what facts about the planet, the lifestream, and mako, were common knowledge, and which things were considered the realm of conspiracy. I'm sure a lot of Shinra people knew the key deets, such as Lucrecia. When most people die on screen in the compilation, the lifestream is visible, so I guess it's hard to be completely ignorant about it.
I haven't played the OG in far too long (almost a decade- wtf, it feels like just a few years ago - I just don't have the patience for random encounter mechanics anymore...) so I don't remember a lot of NPC dialogue. So I apologize if this is a stupid inquiry that is easily resolved by material buried in the fugue of my memories.