(In the green text below, I'm not quoting the comment immediately above. I'm quoting the points within this fork of the thread that were in response to my OP as well as the responses to those, in one place, responding to them all.)

>Mary was bestowed with an ongoing grace prior even to Christ's conception, in a way that is unique to her. She held Him within her womb.
>Mary was either preserved from temptation in a particular way or simply chose not to sin

Every Israelite was in sin. "There is none righteous, not one... except Mary. I swear on my mama."
The conceptual misunderstanding, an itch, that needed scratched that led to the idea/solution of a sinless Mary is the wrestling with how Christ would be sinless if born through a fallen human--the same state that results in other humans being in sin.
(The answer: It wasn't the same state--not because Mary was sinless or in some special grace, but because Christ is a second Adam in that he has no father by the Spirit but God. He is descended by flesh from Adam, but not descended by Spirit from Adam. He is rather by the Spirit the ancestor of Adam, as He is God, who gave His Spirit to Adam. That is why He is the true vine and we are the branches.)

It's unnecessary for Mary to be sinless, let alone inconsistent.

Let alone insufficient, really, if we were to trace that, too.

>If Mary was sinless then her death would have been a perfect sacrifice as much as Christ's was

The reason that Christ's death is the sufficient sacrifice is that only the death of the Husband (God) releases the adulterous Bride (all Israelites, living or dead, regardless of whether they were of Judea or whether they were the much greater number elsewhere--even the greater number of Israelites: those having been removed from the congregation so long ago (and their descendants) that they no longer knew/remembered themselves as Israelites) from the vow (the law). With the death of the Husband, the adulterous Bride is released.

Mary dying (i.e. not the Husband), whether sinless or not, would not satisfy this.