Greetings Dr Guthry,
Welcome. Thanks for these excellent questions. May I ask what your background is, and why this interests you? I think that others will give better answers, but I wanted to welcome you.
I’m a family physician who was born and grew up in Africa, the son of medical missionary parents. It’s the difficulty in jiving science (and evolutionary biology) with faith which brought me to this website at the end of last year. I find the moderators and frequenters here to be very kind and thoughtful.
It seems to me that if we were able to define the soul (? responsibility? I’m currently listening to a Youtube by Kenneth Miller on reason, consciousness, and free will–theory of mind, as you say), then we would have more insight on that. Denis Lamoureux, who has PhD’s in evolutionary biology, theology, and a doctorate in dentistry, wrote extensively.Lamoureux's Evolutionary Creation - #3 by Randy (scroll down a bit to Post 3)
George Macdonald seemed to say that if God exists, He has relationship with every one of His creatures–therefore, it would be a continuum, and not a stark division in terms of responsibility. I find that intriguing.
Thank you for your thoughts.