Okay, but, like, bodies still decompose normally in FFVII's universe though, don't they? I posit yes. Bugenhagen specifially mentions bodily decomposition to help Cloud understand how the soul returning to the Lifestream is similar, not literally the same thing:
"Eventually... all humans die. What happens to them after they die?
The body decomposes, and returns to the Planet. That much everyone knows.
What about their consciousness, their hearts and their souls?
The soul too returns to the Planet.
And not only those of humans, but everything on this Planet.
In fact, all living things in the universe, are the same."
I take from this that the human understanding of bodily death in FFVII is the same as in the real world. As in, humans, animals and plants go kaput like we would expect them to, and those left behind can observe the grim transformation of our vessel into worm-food. The "soul" part of death is talked about like it is invisible - just like the real world. Otherwise, the speech wouldn't have the leading question "What about their hearts and their souls?" If it were plain to the naked eye, everyone would already know.
But hey, for all I know, literal pyreflies might be what they decide to run with in 7R2. In which case, won't I look foolish. Living franchises are harder to analyze than dead poets or the one-and-done Final Fantasies from 1-X.
The remake could simply introduce the fact that some people take longer to dissolve into the Lifestream, perhaps based on their will to hang out, hatred, regret, etc...
My will to hang out is strong. I shall linger beyond this mortal coil until the keg is empty and the sun comes up baby!