So Mary was “favored” with God’s grace, or grace had been “bestowed” on her; however, she was not “full” of grace. How much grace did God grant her, then? One-half of her capacity of grace? Two-thirds? I think you are standing on your head , semantically, to avoid asking yourself how she came by grace at all prior to Redemption without being specially gifted by God. And yes, to the Catholic understanding, being full of grace implies freedom from original and personal sin.
Freed after experiencing depravity or excluded from the curse of Adam and never having been under the Curse?
The New Testament was written in Greek for a reason. There was a word that means “full” as was used for Stephen and Christ. It was NOT used for Mary. You can make up what you want but scripture says what it says. The Holy Spirit chose the words He did for a reason.
Christ was the only sinless man to walk this earth since Adam and Eve.