I am going to be tied up for much of the rest of today but perhaps what I previously posted on another thread would give some small contribution in terms of prologue:
I realize that it doesn’t address your main questions but it’s all I can provide for now. I will hope to jump in later. For now I will just say that over the years I’ve tried to nail down exactly what the Bible means by the Image of God and I still cannot say that I am at all close to resolving the disagreements on this even among evangelical scholars.
I will say that I’m inclined to think that the Image of God always entails having free will and an eternal soul.
As to “If they had a free will, how did they not sin?”, I think that a Divine-aware creature having free will typically has the choice to sin or not sin in a specific situation. Beyond, I will state that my Molinism probably motivates most of my answers to your follow-up questions which will probably arise from these topics.
@cdods, I see that you joined the PS forum many months ago—but I don’t recall our interacting much in the past. So if I haven’t already done so, I extend my welcome to you. I’m delighted to see you introduce this interesting thread. (And being an “unconflicted Christian” sounds like a good thing to me!)