“In as much as Christ has made St. Mary our Mediatrix of All Graces, she is our salvation.”
How can that which stands between us and our Salvation be our Salvation? I don’t see that your conclusion logically or theologically follows from your premise.
I note that two of your three quotations seem to undermine your position:
“Through the prayers of the Mother of God, O Savior save us!” (Liturgy of St. John Chrysostom, First Antiphon)
Surely the Saint is asking Our Lord to save him through the prayers of the Blessed Virgin, and not asking the Blessed Virgin to save him.
"…and does not with sincere faith seek her intercessions as of one having confidence in her access to our God…”
Yes, her intercession. She intercedes for us with Our Lord, who is our Salvation. I don’t see how that makes her our Salvation.
I dunno. Seems to me that there are two greetings in latin: 'salve' and 'ave.' Just from the two prayers we know utilizing them, one could conclude that 'salve' is the greeting used by an inferior, (or to establish one's humility vis-a-vis the one who is greeted), whereas "ave" is used by one who is superior.
Without her intercession, no one is saved.