Hi, @jhmulig. I have a bit of a different explanation for the question you've asked: "How do we explain the entry of sin into the world (i.e. fall of man) in a theistic evolutionary perspective?" I hope you mean it when you say that any answer will help!
As a practising cataphatic Christian mystic, and as a fan of the hard sciences and the neurosciences, I started asking God about the questions of sin and suffering, and the answers I got back have all related to the way in which our DNA is structured to allow temporary (i.e. human) experiences of error (sin) followed by permanent insights into the meaning of free will, forgiveness, Divine Love, redemption (as opposed to salvation), courage, trust, gratitude, and devotion.
This relates to metaphysical questions about the soul and the way in which our souls are interwoven in our DNA blueprints to allow these difficult but transformative experiences.
This leads to further questions about baryonic matter (the stuff of life on Planet Earth) and how other forms of God's creative energies (e.g. dark matter, dark energy, magnetism, gravity, etc.) relate to our temporary human forms (which are made of baryonic matter) and our permanent soul consciousnesses (which, I suspect, are linked to dark matter through God's multiple quantum fields).
But if you accept the idea of the immortal soul in combination with Jesus' teachings on forgiveness and love, then it's not so hard to understand why God might have allowed our DNA to include the coding for our colossal ability to make mistakes.
It's only when we make grievous errors, then go through the stages of recognizing, forgiving, and healing our errors (within our human limits, of course) that we come face to face with the true immensity of God's courage, trust, gratitude, and devotion. It's, well, it's an experience that can only be felt and deeply understood after you've walked a mile in these shoes. (And this may explain why we see Jesus walking and walking!)
I feel quite certain that many of God's many children are able to achieve these insights without incarnating as human beings and slogging through all this confusion and pain. But I rather suspect it's God's impatient bunch of children who insist on doing things the hard-but-fast way!
Blessings to you now and always.