What Catholic version of the Bible are you looking at? It seems the stamped version of the USCCB has this:
Luke 1:26-30 NABRE
In the sixth month, the angel Gabriel was sent from God to a town of Galilee called Nazareth, to a virgin betrothed to a man named Joseph, of the house of David, and the virgins name was Mary. And coming to her, he said, Hail, favored one! The Lord is with you. But she was greatly troubled at what was said and pondered what sort of greeting this might be. Then the angel said to her, Do not be afraid, Mary, for you have found favor with God.(NABRE)
I will note there is no footnote either saying some manuscripts have “full of grace.”
So at least for the official RC English Bible they are settled on the matter. It is “favored one.”
And the Greek (charitoō=graced/favored) says the same of all believers:
To the praise of the glory of his grace, wherein he hath made us accepted in the beloved. (Eph 1:6)
1) Mary is called "full of grace" or "most favored one" (your choice!) BEFORE Christ was conceived ("thou SHALT conceive in the thy womb"), born, died and resurrected. We can argue whether she was saved right at this moment of the Annunciation or she was prepared as a pure dwelling place for the coming Christ from her first moment of her own conception but one thing is clear... she wasn't waiting (like the rest of us) for salvation.
2) Mary was greatly troubled by the greeting of the Angel. Note that it doesn't say she was scared of the Angel, she was troubled by his greeting. There is something powerful in the greeting (whatever translation you use) and she recognized it enough to be troubled that she should be called "full of grace" OR "most favored one".