What would be incorrect would be to attribute divine powers to St. Mary. Deification is an easily misunderstood word, as the JW's demonstrate. It means that we realise the image of God in which we are made; it does not mean that we literally become 'God' or 'gods'.
I think you mean Mormons, not Jehovah's Witnesses (who are Arians). I have heard that Mormon apologists have been quoting the Greek Fathers in defense of their perverse heresy. Mormons reading those apologetic works see the term "divinization" or "deification" and they think the Fathers are talking about the same thing the Mormon false teachers are.
Compare these two statements:
As man is, God once was. As God is, man may become. -- Mormon "prophet" Joseph Smith
God became Man, that man might become god. -- St. Athanasius
Those reading with understanding see the sublime understanding of St. Athanasius and the satanic perversion of the Mormon "prophet". It is the same satanic perversion that is expressed in Scripture:
For God knows that in what day soever you shall eat thereof, your eyes shall be opened: and you shall be as Gods, knowing good and evil. -- Gen 3:5 (the serpent tempting Eve)
Dearly beloved, we are now the sons of God; and it hath not yet appeared what we shall be. We know, that, when he shall appear, we shall be like to him: because we shall see him as he is. -- 1Jn 3:2
The difference between orthodoxy and heresy is often the satanic lens of a perversion. The orthodox doctrine of predestination as taught by St. Paul and St. Augustine becomes the perverse teachings of John Calvin (which they call "double predestination"). The orthodox doctrine of deification as taught by St. Paul, St. Athanasius and other Early Church Fathers becomes the perverse teachings of the Mormon religion (which they call "exaltation").
Acts 13:9-10 said:
Then Saul, otherwise Paul, filled with the Holy Ghost, looking upon him, Said: O full of all guile, and of all deceit, child of the devil, enemy of all justice, thou ceasest not to pervert the right ways of the Lord.
Gal 1:6-7 said:
I wonder that you are so soon removed from him that called you into the grace of Christ, unto another gospel. Which is not another, only there are some that trouble you, and would pervert the gospel of Christ.
I quipped elsewhere a while ago that the problem with Mormonism isn't that they think too much of man but that they think too little of God. They have a boring, little God if they think that God was once a man (cf. Num 23:19 and Is 55:8-9). They thus deny the infinitude, greatness and transcendence of God. What small-minded thinking it is to think that there could be more than one perfect Will? There is the perfect Will of God and a multitude of imperfect and evil wills. The Saints are in Heaven because they conformed to the Will of God. It is far harder and more crucial for a martyr to say "yes" to God than "no" to their captors. It seems at first glance that the Mormon religion offers a greater hope for the afterlife than the Christian religion but it is a much greater thing to behold our great God than to be like their God, who is like one of the pagan gods.
This notion of deification notion is not foreign to Protestants, they refer to the glorification and sanctification. Christian perfectionism is a Protestant a doctrine that an individual could become perfectly conformed to God while on earth and thus free from sin and unable to progress further in Grace (declared a heresy by the Catholic Church in 1311). Wesleyan denominations (Methodists) teach a variant of this doctrine called "entire sanctification". Lutheran pastor, activist and victim of Auschwitz, Deitrich Bonhoeffer said of Christ (echoing St. Athanasius): "He has become like a man, so that men should be like him."
Speaking very broadly, just as your signature quotes Bar-Hebraeus in saying that all of us (EO, OO, RC and most Protestants) accept that Christ is two natures with two wills in one Person, I would suggest that the various ways that we speak of salvation, the Resurrection and the sharing of the glory of God, partaking of the divine nature -- St. Paul refers to it in several ways -- is our weak attempts to express with human language the incalculable glories which await us, God willing, as the elect. Whether we say "salvation", "theosis", "deification", "divinization", or "glorification", we all mean the same thing. None of us in this thread are followers of Joseph Smith or Herbert Armstrong, we believe in the Trinity. We don't believe that a human being can possess the divine nature, become God, but rather that we may "partake of the divine nature", to be eternally with God and to "see Him as He is" (what we Catholics call "the Beatific Vision").
2Pe 1:3-4 said:
Quomodo omnia nobis divinæ virtutis suæ, quæ ad vitam et pietatem donata sunt, per cognitionem ejus, qui vocavit nos propria gloria, et virtute, per quem maxima, et pretiosa nobis promissa donavit : ut per hæc efficiamini divinæ consortes naturæ : fugientes ejus, quæ in mundo est, concupiscentiæ corruptionem.
As all things of his divine power which appertain to life and godliness are given us through the knowledge of him who has called us by his own proper glory and virtue. By whom he has given us most great and precious promises: that by these you may be made partakers of the divine nature: flying the corruption of that concupiscence which is in the world.