b. I'm not sure what you take 'free' to mean, in "...sin is caused by....a free will choice to rebel".
My take on the meaning of our free will is a little more involved than orthodoxy likes us to look...
All FREE means is uncoerced and unconstrained:
IF GOD set it up so HIS new creation had no coercion or constraints upon their choices, forcing them to choose anything good or bad, they had free will.
The Elements of a True Free Will Choice:
1. Free will can't be coerced:
Nothing in their created nature could
FORCE them to choose love or hate, good or evil, including all genetics, cultural or familial values or experience...
Nothing in their understanding or knowledge of reality could
FORCE them to choose good or evil, love or hate.
In other words, they had to be completely and truly
ingenuously innocent.
[Ref: definition of
ingenuous: [URL="http://www.thefreedictionary.com/ingenuousness"]ingenuousness[/url] as: 1. Lacking in cunning, guile, worldliness; artless. 2. Openly straightforward or frank; candid.
2. Consequences must be known but not proved:
The person must understand the full possible consequences of their choice or it is a guess, not a true choice. “What will happen if I choose left or right, the red pill or the blue pill?” must be answered in full detail.
But
"PROOF" of the nature of the consequence would compel or coerce the person to choose what was proven to be the best for them. If the answer
“death here,” “life there,” was proven, which would you choose? The weight of knowledge would destroy the effect of a true ‘free will’ choice.
If it were proven you would die if you went left, are you truly free to choose to go right? No, you are forced by your knowledge to go right. Therefore they must know, but without proof, the nature of the natural and legal consequences of their choice.
Only then are they following their desires, their deepest hope in the nature of reality, defining and choosing for themselves the reality they most hope to enjoy. This kind fo choice is a free will decision based upon faith, an unproven hope.
Peace, Ted