As I wrote, I created that diagram without having sought any scholarship in support. I started with "death" because in my mind I imagined Humans and others such as the Neanderthals, living hundreds of thousands of years ago, grieving over the deaths of their loved ones, whether through illness, attacks from wild beasts, or from enemies. Archaeological evidences reveal the care they took with the remains of the departed. This sense of grief is not confined to us as a species.
In my diagram, I made the hypothetical assumption that grief evolved into a hope, which then developed into the idea of a spirit world (often seeing the world of nature manifesting actions by the spirits). The nature of this spirit world reflected the hierarchical structure of their communities, with an upper echelon of super powers, the gods.
I then imagine that over time, questions arose regarding ethics, morality and so on, and in the process this created the concept of sin, along with the consequent necessity to address it. One such resoluton is theodicity. Another outcome for Christians was to provide a reason for Jesus' death, which they did by believing that the Adam story is truth.
As I research the views of the formative church, today I came across the following, which supports my hypothesis that the narrative began with Death but that the Church later reversed this to say that the story began with Sin.
Doug
==========================
"The crucial question of origin for the Hebrew writers and earliest
Christian writers was more about the origin of death than of sin. Why are human beings created only to face death?
Why is the created order, a product of divine goodness, the source of tragedy
and suffering? These dilemmas invite a theodicy, an explanation of how God is
powerful, good, and loving and yet there is evil. Death faces humankind as an
evil. To attribute to sin the introduction of death into the created order
places the blame for such evil on the side of humans, not God. By their
rejection of God’s will, it was argued in both the Hebrew and Christian
traditions, human beings brought death into a world where it had been absent.
Death is the punishment for sin." (Original
Sin, Wiley, page 53)