On Luke 1:28, you rely on obfuscatory Protestant translations, designed to propagate mariophobic falsehoods.
The original says “Kecharitomeneh”, a unique to Luke word formation from “charis”, “grace”. It is true that “charis” is sometimes translated “favor”, but never in theological context. The same Protestant translations that have “favored” in Luke 1:28 always translate “charis” as “grace” everywhere else. It is simply a dishonest attempt to trivialize the manner of the angel’s salutation, even though St. Luke makes a special effort to underscore its uniqueness in the following verse.
Further, “kecharitomeneh” is past tense, — something English translation cannot properly convey. This points to the fact that Mary is not filled with grace at the time of the Annunciation, but that she had been filled with it all along, hence Immaculate Conception.
St. Stephen is also described as “full of grace”, but the context is clear that he experiences a surge of grace and fortitude as he speaks, and the origional uses a different verbiage.
The woman in Apocalypse (Revelation of St. John) is described as mother of Christ (Apoc. 12:5, 10). The interpretation that she is somehow Israel is just plain silly.
Actually, I looked up that passage about St. Stephen. I found in the KJV that he was filled with FAITH, not grace. Further, the underlying Greek word is that translated as “faith,” not grace... it has nothing to do with “charito.”