LicoriceAllsorts
Donator
FWIW, it seems to me that the basic idea was meant to be that no one's consciousness survived death. An individual's spirit energy, the thing that animated them, returned to the Lifestream and their body... dissolved? Or decayed in the usual manner? So after the individual dies, all that is left of them is their effect of their actions on the world and people's memories of them. Zack and Angeal's post-mortem appearances in ACC and Crisis Core could be dismissed as near-death hallucinations on the parts of Cloud and Zack respectively, but Aerith is clearly still acting on the planet after her death and canonically she is IN the Lifestream. That leaves it open to believe whatever one wants. It all depends on whether one thinks she's a unique exception or not.
Maybe human beings (and Nanaki's species too) have souls as well as spirit energy, and enjoy an afterlife somewhere off-planet or on another plane of existence that transects with the plane of the living. In His Dark Materials, Philip Pullman's characters had bodies, and souls (their daemons), and also consciousnesses which survived death but were imprisoned in some sort of dreary underworld afterlife.
Maybe human beings (and Nanaki's species too) have souls as well as spirit energy, and enjoy an afterlife somewhere off-planet or on another plane of existence that transects with the plane of the living. In His Dark Materials, Philip Pullman's characters had bodies, and souls (their daemons), and also consciousnesses which survived death but were imprisoned in some sort of dreary underworld afterlife.