“natural” is probably not the right way to explain it. I think they key point we are doing is creating a new theological category: “those outside the garden.” We can make some inferences about what is going on with them, but very little is directly said.
What have put forward is that Adam and Eve’s original mission was to bring them into the Garden, which implies they were worse off outside the garden. You can see a graph of this below, noting that the grey reminds us that Scripture is largely silent about them, because they do not exist any more.
However, Adam fell, and then caused those outside the garden to fall too. Once again, Adam’s fall is the fall of all mankind. Scripture does not mention much about those outside the Garden, because they no longer exist.
So the key questions you are asking are all resolved, I’m certain, by this new third category, while remembering that traditional theology sometimes speculated about the, but certainly never made any strong statements about them. Because of this silence, we have a free variable now that enables us to resolve all the puzzles you’ve raised.
So, what is the Garden like? We could say, (1) in the presence of Yahweh’s theophany in a special way, (2) free of physical and spiritual death, (3) initially free of wrongdoing and transgression, (4) free of working by the sweat of our brow, in a land free of thistles, and (5) free of pains of childbirth. The Garden, essentially, might be exactly and literally as described by traditional theology, as long as we remember that it had borders. This was Adam and Eve’s natural state, into which they are created.
So what was the Fall like? In the narrative, the Fall is a process of exile, where (1) access to the Garden is cutoff, (2) Adam will now have to eat by working the land, full of thistles, (3) Eve, and all her daughters, would now face pain in childbirth, (4) both would now face physical and spiritual death, and (5) they and all their descendants would be subjection to transgression and corruption. By transgression here, I mean both original sin, and also the consequences of knowledgeably violating a divine decree with wrongdoing.
So, what about outside the Garden, before the Fall? So, to resolve the questions you are raising, we could can imagine that outside the garden (1) there was wrongdoing, but this was not knowledgeably violating a divine command, (2) there was physical death, (3) there was pain in childbirth, and (4) there was effort required to eat (hunting or farming). This was the beginning state of those outside the Garden.
So, clearly the Garden is better than outside the Garden, but the Fallen world is worse.
We can adjust the qualities of those outside the garden as needed, because both Scripture and theology is largely silent about them. Though there are hints. For example, Romans does make a strong distinction between knowledgeable and ignorant wrongdoing (both of which are “missing the mark” and referred to by hamartia). Like wise, the Genesis narrative makes clear that Adam was created conditionally immortal, reliant on the Tree of Life for mortality, which did not exist outside the Garden. As long as those outside the garden are worse of than those in the Garden, but better of than the Fallen, we have a coherent story.
Once again it comes down to what we mean by “human”. Scripture refers exclusively to the descendants of Adam, and for them the explanation of human death and suffering is Adam’s transgression. For those outside the Garden, Scripture is silent about them, but God intended to bring them into a death free Garden, before Adam fell. So Adam’s fall, his transgression, caused a great deal of death and suffering, but they are not the “humans” to which Scripture refers.
And the narrative does explain these key features of the human condition. This is not what God intends for us, and he initially created Adam in an environment free from it. Because of his transgression, we lost access to this gift. We still long for the Garden, even though it is gone. As descendants of Adam, in our history we once tasted it, but then our ancestors chose something different, and we are all not suffering.
Really nothing of our story changes by acknowledging that there were, a very long time ago, people outside the garden. Perhaps they were created in a different way, but Adam, our first parent, was created exactly as God intended it. Adam’s story ends up dominating our story, because we are Adam’s children.
Does that not leave traditional theology entirely intact?