[In Judges 6:12 the Angel of the Lord says to Gideon, "The LORD is with thee, thou mighty man of valour." In this case the Hebrew vocative is not a statement of absolute fact! It was said to Gideon when he was hiding in fear of the Midianites. He became a mighty man of valor, but this was not the case when the words were spoken.]
Stephen is said to be full
GREEK:
pljrjv, ev sometimes indeclinable; (1) of space fully occupied full (of), filled (with), with the genitive of what the filling consists; (a) literally, of things full of, filled with (MK 8.19); (b) figuratively, of persons full of, filled with, rich or abounding in, thoroughly endowed with (LU 4.1; AC 9.36); (2) of a totality of something or someone with nothing lacking complete, in full, wholly filled (JN 1.14); of grain fully ripe (MK 4.28)
of grace.
***Mary is found to be "she who is full of grace" (or 'she who is highly favored' - in most Protestant translations) long before she does or says anything having to do with God's plan for the Incarnation of His Son.***
Right, she was a godly woman. One in whom God's grace was exemplary.
***In Stephen's case the adjectival formula stresses its donation of 'grace and power' to him from God for his apostolic ministry.***
Both Mary and Stephen were exemplary recipients of God's grace. Both honored the Lord in obedience to the Divine call upon their life. Mary gave birth to and nurtured our Lord. Stephen gave his life as the first martyr.