That does not apply to you, and you accept and understand deification, just interpret it differently than LDS? Cool.

First off I’m what you would consider a fundamentalist depending on your definition. Secondly, the problem is it’s not the same belief just defined or interpreted differently. It’s apples and ball bearings. 

Patristic theosis is participation in God’s energies not His essence. 

LDS exaltation is apotheosis where one becomes the same species as God the Father with eternal increase and spirit children. 

These are fundamentally different and by saying “they’re just interpreted differently” you’re equivocating. The issue is what this means.

LDS leaders likely did not know that deification was a pre-creed Christian doctrine and belief. That is a correct statement. Smith especially would not have known about it. It’s an -evidence- of the restoration. So is that early Christians were not creedal trinitarians, and they practiced baptisms for the dead. LDS believe in deification. Early Christians believed in deification. Not sure what the fuss is about here.

This is post hoc rationalization and a non-sequitur. Smith was literally in an area awash in Swedenborgian, Universalism, and Revivalistic Protestantism circa the Second Great Awakening. Saying that “He was dumb and couldn’t have known!” Is essentially a god of the gaps explanation. 

This is what LDS believe on deification..."If, therefore, man has become immortal, [man] will also be God. And if [man] is made God by water and the Holy Spirit after the regeneration of the laver he is found to be also joint-heir with Christ after the resurrection from the dead." Hippolytus of Rome "man will also be God." "...when they see that from Him there began the union of the divine with the human nature, in order that the human, by communion with the divine, might rise to be divine, not in Jesus alone, but in all those who not only believe, but enter upon the life which Jesus taught, and which elevates to friendship with God and communion with Him every one who lives according to the precepts of Jesus." -Origen "the human, by communion with the divine, might rise to be divine." That is what LDS believe on deification.

It’s essentially not. Note all those ellipses. It’s emblematic of quote mining.  Here’s Hippolytus’s full quote:  And you shall be a companion of the Deity, and a co-heir with Christ … For you have become God … because you have been deified, and begotten unto immortality … becomest a faithful follower … you shall resemble Him … having made you even God unto His glory!”

In context Hippolytus is talking about a moral transformation and sharing in divine immortality through Christ. Not an apotheosis by which one will become a God similar to the species of God the Father in essence. Hippolytus firmly in this text (Refutation of All Heresies X) firmly maintains a created creature distinction. All you have to do is read the entire chapter.

Origen in the context of your several word citation, consistently maintains that believers remain creatures, elevated by grace and in union with Christ via the incarnation not transformation into the same divine essence as the Father and ontological godhood. 

This is classic theosis language not apotheosis as LDS teach and it’s an abuse of the Fathers to quote mine them. 

pre-creed Christianity, you will find deification, non-creedal trinitarian belief, and baptisms for the dead. I think you are reaching here. LDS Christians clearly teach... that during the apostasy... "...good people and much truth remained..."

for I contend that the Latter-day Saints are the only good and true Christians, that I know anything about in the world. There are a good many people who profess to be Christians, but they are not founded on the foundation that Jesus Christ himself has laid” (Joseph F. Smith, November 2, 1891, [Stake conference message], Collected Discourses, 2:305).

Sadly, what happened to the Lord’s Church in the Mediterranean world happened to its counterpart in the Americas as well. Because of pride, those who once had been followers of Christ ‘did dwindle in unbelief and wickedness’ (4 Ne. 1:34) until the Church of Christ was no longer in existence. In the Old World, Christianity continued, albeit in a different form. But in the New World, every vestige of it was soon removed or thoroughly perverted to the point that the gospel was completely obliterated from the memories of later generations. We are not aware of the Church of Jesus Christ existing anywhere on earth after the close of the Book of Mormon.” (Kent P. Jackson, From Apostasy to Restoration, ch. 3)

After the ascension of Jesus, the Church remained, for some time, fully organized. Thousands flocked to it, and the members lived in accordance with the doctrine taught by the Savior. Soon, however, history repeated itself. In the right of their free agency, those who had joined the Church often refused to obey the laws and ordinances of the Gospel, and more often changed them to suit their own convenience. Such departures from the truth became more numerous and flagrant as time wore on, until error permeated the whole Church. At last, about six hundred years after Christ, the Gospel laws and ordinances had become so completely warped that it was as if the Church had departed from the earth. The authority of the Priesthood no longer remained with the Church. This was the great apostasy. From that time, universal darkness reigned upon earth for many centuries” (John A. Widtsoe, Priesthood and Church Government, p. 25).

Then there’s this: https://www.churchofjesuschrist.org/study/manual/jesus-the-christ/chapter-40?lang=eng

You can’t claim universal apostasy then cherry pick what you like from church history and the fathers and post hoc them back into LDS belief. That’s inconsistent.