"Kecharitomene" is used just this time. A trip to a concordance shows that; I gave you the online resource. Other formations from "charis", naturally, are used throughout the Bible.
The plain meaning of the text is whatever blessing His mother has is available to anyone who follows Him. He is saying there is nothing special about her blessing for He uses the same word
That is true, and indeed Mary has received the same grace we all receive. There are no different kinds of grace. Yet, the woman venerated Mary and Christ agreed with His "Yea".
You forgot the 'rather'.
Mary was blessed for bearing the Lord.
But that was over.
Now she was no different from anyone else and was blessed by taking in the word of God like anyone else.