I am sorry to learn that you prefer non-Christian commentators to Christian ones. For myself, I would sooner trust the word of God which the Jews rejected, namely the New Testament and Romans 5 in particular.
Rom 5:6. 'For when we were yet without strength, in due time Christ died for the ungodly.' Paul has already established (Chapt. 3) that all men are sinners. Here h also says that we had no strength to make ourselves right with God. Since brute strength is not required to be right with God, 'strength' here must mean 'ability.' Where did this lack of ability come from?
v12. 'Therefore, just as through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned.....' There was no sin before Adam fell, and death came through Adam's sin (Gen 3:17-19). But it came, not just to Adam, but to all men, 'because all sinned.' Does this mean that all men die because of their own sin? Yes, it certainly means that, but it means something more.
v17. 'For if by the one man's offense death reigned through the one......'
v18. 'For as through one man's judgement came to all men resulting in condemnation.....'
v19. For as by one man's disobedience many were made sinners, so also by one Man's obedience (cf. Phil 2:8) many will be made righteous.' Do notice how many times the Holy Spirit makes Paul repeat himself here. Perhaps it's because it's important.
Adam was our covenant head (or 'representative head' if you prefer). He acted on our behalf. When he fell, we fell and were constituted sinners by his disobedience. We owe God a debt of obedience which Adam transacted on our behalf and which we are by no means able to pay.
However Christ prevailed where Adam failed, and He also is a covenant Head of all those whom God has given Him (John 6:39 etc.). He has paid the penalty which Adam's fall invoked and He has wrought a positive righteousness for His people by His perfect obedience to the Father's will.
Oh loving wisdom of our God,
When all was sin and shame,
A second Adam to the fight
And to the rescue came.
Not at all. Paul says repeatedly that Adam's sin is passed on to us. However, no one but Adam and the Lord Jesus is our covenant head, and therefore no one's sin is passed on to us but Adam's and no one's righteousness except our Lord's. therefore Ezek 18 is (of course) entirely in line with Romans 5.
Finally, if we deny that Adam's sin is imputed to us, how can we suppose that the obedience of the Lord Jesus will be imputed to us?
This is pure supposition. Do you suppose that we won't eat in heaven (Isaiah 25:6-8; Rev 19:9)?
One last thing; if Adam and Eve had a 'sin nature' before th Fall, God thought that it was 'very good' (Gen 1:31).
I must say that I had supposed that the pelagianism of Oberlin theology and Finneyism were things of the past.
Steve