Doug,
Well done! I am in agreement to what you have written up to this point. The one point I would discuss (not necessarily disagree with) is Romans 4. You spoke of him offering up Isaac, but that is not what Romans 4 is referring to. It's simply speaking of him (Abraham) having faith that he and Sarah were going to have Isaac when they were both too old (by human standards).
The interesting point is that they weren't really perfect in faith here... Sarah suggested Abraham sleep with the younger Hagar... That produced Ishmael. But that wasn't the promise. However, they still had faith to get the job done according to God's plan.
As for offering up Isaac... That wasn't considered a work according to Hebrews 12. If that account is accurate, Abraham offered him up -- willing to kill him -- but still believed the linage would continue through Isaac. According to Heb 12, Abraham expected God to raise Isaac from the dead.
So yes, it was obedience... But it was the faith that God was still going to deliver the promise even if Isaac died. Abraham simply believed he (Isaac) would be resurrected.
This may be works as evidence...but only with men... Not God! God didn't need Abraham's works; he needed his faith.
So when you look at what James said:
James 2:18 KJV
Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works.
James is talking about people seeing faith by works. It's sad, but man needs the physical evidence! They need to see works to see faith. Now look at Paul:
Romans 4:2 KJV
For if Abraham were justified by works, he hath whereof to glory; but not before God.
These two verses oddly agree. You got works, you can glory before men. But not God! James was looking to prove to men he had faith by his works, but Paul said it is glory, but not before God.
I can throw in Matthew 6, here... The opening 10 or so verses say don't give, pray or fast to be seen of men. Do it in secret before God.
Again Doug, well done! I bring this up not to question your excellent postings, but to further the discussion.