That seems reasonable, if, by deification, you mean the soul eventually achieving perfect oneness, perfect unification with God’s divinity and perfect conformity to God’s will?

It is perfect oneness with Jesus, through the Holy Spirit.
Hey, you definitely points for originality, and sadly bolster the lies spread by many protestants claiming that catholics worship Mary.
There was a time in our history when Arians far out numbered orthodox and most outsiders saw the Arians as if they were the Church. But the few that worshiped Jesus as God would bolster the lie the Church (actually the Arians) worshiped Jesus. It was a very hard thing to learn to confess that a man could be God. And like it or not, it is even harder to learn to confess that a woman could be God.
Do you worship the Holy Spirit?
" The true worshippers shall worship the Father in Spirit and in Truth: for the Father seeketh such to worship Him. God is a Spirit [lit. “The Spirit is God”] : and they that worship Him must worship Him in Spirit and in Truth. " (John 4:23-24)
Jesus said: “I will build my church…” (singular)
From that you get: …
I don’t get anything from that verse in so-called “Gospel according to Matthew”. There is a very good reason that verse is ONLY in Matthew and not in the other Gospels. But we would go WAY OFF topic to get into that, so continue …
- “Jesus and the Apostles established Churches (plural) mainly for the Gentile Christians.”
- “Jesus and the Apostles established Christian Synagogues for Jewish and Samaritan Christians.”
Who holds the primacy in church #1 and church #2?
Getting off topic a bit. I brought this up because I thought you needed to know where I was coming from since I am the only one speaking up for the Most Holy Virgin’s full divine honor. But, at the risk of starting a major tangent, the short answer is that before anyone started to speak of a primacy in St Peter, it was St James (Jacob - I hate calling him James because the name is Jacob, but no one will understand me if I don’t say James) in Jerusalem that lead all Churches and Synagogues in the beginning. Consider this one verse from the so-called “Gospel according to Philip”, " The disciples said to Jesus “We know that You will depart from us. Who is to be our leader?” Jesus said to them “Wherever you are you are to go to James the righteous for whose sake heaven and earth came into being.” " (According to Philip, verse 12)
Considering the scriptural fact that Jesus prayed that His community be one and united just as He and the Father are one, do you believe that Jesus wanted those gentile Christians belonging to one church and those Jewish/Samaritan Christians belonging to another church, to be one and united as a community as well as doctrinally speaking?
" And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice; and there shall be one fold, and one shepherd. " (John 10:16)
Ok, about this oneness that all Christians have: I will use this to get back on topic. (There’s that word “all” again! “all have sinned…”). “One Lord, One Faith, One Baptism”. It is baptism that gives us our oneness (not the Pope, sorry, the episcopal oneness of the Pope is for the Gentile Churches only).
“Can he enter the second time into his mother’s womb [that would be the womb of the Virgin Mary!], and be born? … Except a man be born of water and of the Spirit [lit. “of water even the Spirit”], he cannot enter into the Kingdom of God. … That which is born of the flesh is flesh; and that which is born of the Spirit is Spirit”, “as many of you as have been baptized into Christ have put on Christ”, “For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.” (various Bible versus)
How does baptism make us “put on Christ”? By the Holy Spirit we spiritually enter the womb of the Virgin Mary and are born (baptized) into Christ. We are “born again” from the womb of the Virgin Mary (physically water, spiritually the womb of the Holy Spirit) into the perfect oneness of Jesus. This is why the Church was “born” on the day of Pentecost by the Holy Spirit, even Mary, who was the central figure on that day because She was and is the Holy Spirit!
So, “For all have sinned, and come short of the glory of God” means that, “For all have sinned, and come short of the glory of [the Father]”, “For all have sinned, and come short of the glory of [the Son - Jesus]”, “For all have sinned, and come short of the glory of [the Holy Spirit - Mary]”
I confess that I am a sinner and I fall short of the glory of the one Whom the Church says is “more honorable than the Cherubim, and beyond compare more glorious then the Seraphim”, the one Who without corruption gave birth to God!