When, despite this overwhelming (but not coercive or puppeteering) assistance of God's grace, Adam and Eve knowingly did wrong, the graced righteousness that had up to that point surrounded them and drew, wooed, pushed, attracted them (but did not force or coerce) to do right, was gone. It had to be gone because God's righteousness which he had surrounded them with cannot coexist with active sin.
So they lost for themselves and every human being since them the original righteousness of their original graced existence. God comes back with redemptive grace, yes, ultimately the redemptive grace of the Cross but even before that preliminary forms of grace: salvation in crossing the Red Sea, the grace of the angel of death passing over the bloodmarked doorposts in Egypt, the grace of the law itself, the grace of all the prophets' teaching, all of these graces culminated in the once-for-all act of redemption on the Cross.
So they lost for themselves and their progeny the original righteousness that so aided them to choose rightly, but that does not mean that God gave up of them and they were not abandoned by other means of God's grace. The disorder produced by being deprived of the original righteousness meant that their descendents, we, could scarcely choose right rather than wrong (after reaching the age of reason) if not aided by the grace of baptism, the grace channeled through loving parrents who teach us to choose right, the other sacraments that come after baptism, and the many other graces that God gives. We come into the world in a state of disorder in which the aids to doing right that Adam and Eve had are missing but in which a different set of aids (baptism, which removes the disorder, though traces remain in concupiscence) has been given us since Adam and Eve and especially since Christ. We are free, as Adam and Eve were, to reject those aids and choose to do wrong. We find it easier to choose wrong because we lack the original righteousness enjoyed by Adam and Eve.
Baptized Christians no longer suffer from the disorder of congenital lack of original righteousness. So they are better prepared to accept the other graces God gives them and which they absolutely need in order to choose rightly (sola gratia). But they can still, if they choose, after being baptized, reject all those grace-aids God gives them and choose to sin and reject God.
The unbaptized have not had the original disorder/lack of original righteousness removed. They still receive graces to help choose rightly as they learn right from wrong, as they encounter acts of genuine love from other people, as they might hear the preaching of the Gospel etc., or even observe the beauty of God's creation--that too is a grace that can, if received rather than rejected, lead one to choose right rather than wrong--but they have a larger hurdle (lack of original righteousness) to overcome. They can overcome it--solely with God's help, sola gratia--but it's a bigger reach.
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.