This is an excellent exposition of patristic thinking on what happened before and at the Fall as well as on what Free Will means. Orthodoxy does look at a couple of things a bit differently, or would speak of them differently. Rejecting the "aids to grace" in and of itself is not sin, though certainly it could be. All the aids to grace do is allow us to die a bit to the self, thus opening ourselves to God's grace which effects to a greater or lesser degree the theosis we were created for. Sin is choosing to remain "human like" and refusing to become "like God"; as I have said elsewhere, it is "missing the mark" which is Christ. You also speak about the Redemptive grace of the Cross. Here's something Orthodoxy agrees with but wouldn't speak of it that way. It is the entire Mystery of the Incarnation which restored our pre-Fall righteousness (which Orthodoxy believes was a potential theosis) not only the Cross (I understand that the Latin Church doesn't say it was only the Cross). In fact, Orthodoxy focuses more on the descent into the place of the dead and the Resurrection than the Crucifixion.
I normally include Incarnation, Death, Resurrection but I get tired of typing it all. The Cross without the Resurrection would have accomplished nothing, the Incarnation led inexorably to the Cross, if He had not died on the Cross there'd have been no Resurrection or descent to the place of the dead in triumph etc. So my use of Cross to epitomize the drama was not meant to deny any of the others.
It is true, of course, that devotion to the Passion has been characteristic of Latin Catholicism far more than Eastern Orthodoxy. It is so very clear (and is found already in Augustine) but this is one Western characteristic I have yet to figure out an explanation for. It is not a doctrinal matter that conflicts with Eastern emphases on the Resurrection and descent into the place of the dead--we Westerners love the Resurrection too. Rather, the differing emphases in my view are much closer to differences of taste and mentalite that undoubtedly stem from some of the ancient cultural differences between Greek East and Latin West. So you are right to underscore that I used the term Cross as my epitome and that Orthodox would choose a different epitome but we have in common a practice of epitomizing, of drawing the epic drama to a point for the sake of brevity or some other reason.
I appreciate your irenic spirit and firm defense and explication of the Orthodox faith. I seek to do nothing other than that with the Western tradition.
For clarification. I was not saying that rejecting grace-aids was itself sin. I wrote elliptically to try to be brief(er). In order to choose to do wrong (that's what sin is) one has to ignore, reject, refuse all the help God constantly gives us to choose to do right. The sin lies in the doing, the choosing, of wrong. But if one chooses to do wrong, then one will have in fact rejected grace assistance, because if one had accepted grace assistance, if one had gone along with grace, one would have chosen to do right.