That's precisely what it does require.
Joseph Smith was well aware of this, which is why his doctrine required an entirely new revelation and an entirely new set of Scriptures.
LDS belief is irreconcilable with historic Christianity, unless one believes as Smith did that historic Christianity was later supplemented by a new revelation.
it only required accepting that Jesus Christ is the Savior
Incorrect.
Oneness Pentecostals call Christ their Savior, yet they believe that the Son and the Father are just aspects of a indistinct Unity, and not Persons of a Trinity.
Therefore, OP believers have rejected historical Christinaity in favor of a novel teaching.
We believe that the Father and the Son are both eternal.
Eternal according to the LDS definition of eternal.
LDS believers also believe that there was an era before eternity when the Father was a man of flesh like we are, just as LDS believers hope that they themselves will become an eternal deity in the future.
When Christians say eternal, they mean that no being ever existed before God and that God was always as He is now.
showing them to be separate beings
Those passages show them to be distinct Persons, not separate beings.
So who is Christ's Father and God?
The first Person of the Trinity, God the Father.
Did Christ want the apostles to meld into a being of one substance?
No, he wanted the Apostles to be as united with God the Father as the soul and body of the man Jesus of Nazareth are united with the Father - in perfect charity.
How can the Father be greater than Christ or how can Christ go to the Father?
The Christ is two natures united hypostatically in one person.
Jesus the Christ has a body and a soul, like you or I. Unlike you or I, his body and soul are inseparably united to the divinity of the second Person of the Trinity.
And so, insofar as Jesus the Christ is a man, he is inferior to the Father and he needs to be brought to the Father. Insofar as the Christ is the second Person of the Trinity he is coequal and coeternal with the Father and omnipresent with the Father.
I'm sure you have some way of fitting those verses to the doctrines you accept, but don't call me a non-Christian for disagreeing you your interpretation of scripture.
The LDS is a non-Christian faith not so much because it disagrees with Christians in the interpretation of the Christian Scriptures, but because it has introduced a new revelation with new Scriptures - both of which offer a system of belief completely foreign to historic Christianity.
I cite Galatians 1:8, which is not a mysterious verse open to numerous interpretations but a rather plainspoken statement:
But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
It does not say: "But though we, or an angel from heaven, unless the being claiming to be an angel says that his name is Moroni, preach any other gospel unto you than that which we have preached unto you, let him be accursed."
Christianity is a fact of history. The LDS faith is a new faith, distinct from Christianity, with a new scripture, a new revelation and a new prophet unknown to any Christian who ever lived before Joseph Smith made his alleged discovery.
"That's precisely what it does require."
Check a dictioinary, orthodoxy is not required, only an acceptance of Christ as the Savior.
As for the 'other gospel' thing, we consider orthodox Christianity to be another gospel that evolved into existance after the apostolic age. We believe that apostacy is what requried a restoration of the fulness of the original gospel though a prophet. Time will show who is right and I'm content to leave it at that.