In my journey to a full assurance of faith concerning the ultimate reconciliation and salvation of all, I began as a literalist from a Pentecostal/Charismatic background.
The thing that arrested me, after being presented with the UR paradigm from the scriptures was this.
There are a lot of scriptures that overtly declare that all will be gathered into one in Christ, subjected to Christ, reconciled to God through Christ, etc.
Those verses, Eph 1:9-11, Col 1:15-20, 1 Cor 15:22-28, Romans 11:31-36, John 12:32, Rev 21:5, when looked at together, were an inescapable network of understanding for me.
When viewing Phil 2: 9-11 integrated within the context of those verses…
“For this reason also, God highly exalted Him, and bestowed on Him the name which is above every name, so that at the name of Jesus every knee will bow, of those who are in heaven and on earth and under the earth, and that every tongue will confess that Jesus Christ is Lord, to the glory of God the Father.”
.....it was no longer possible for me to conclude that God would cause all to bow the knee and confess the Lordship of Christ to the Father's glory- just before casting them into the lake of fire for eternal torment or annihilation. It became apparent to me that either those verses were all true in context with one another and without exception, or the scriptures themselves were without a measure of intergrity that qualified them as the "word of God/logos". God cannot, "reconcile all", "gather all things into one in Christ" and become "all in all", if multitudes are tormented forever or annihilated.
A true literalist does not have the option of deciding which verses are literal and which verses are not. Even the metaphors of scripture, the prophetic images and the parables, must integrate with the entire body of the scriptures, without contradiction. Any apparent contradiction provides a reason to press into further understanding, into deeper ground, until the paradox resolves, opening up into a new paradigm.
The scriptures interpret the scriptures, and if their integrity is not absolute, than they are of no value whatsoever for foundational truth and doctrine.
According to Paul, God will become all in all…
1 Cor 15:25 For He must reign until He has put all His enemies under His feet…28 When all things are subjected to Him, then the Son Himself also will be subjected to the One who subjected all things to Him, so that God may be all in all.
Clearly, after every knee has bowed all, including the enemies who have been subjected, on earth, under the earth, in heaven- God will be ALL IN ALL.
… For from Him and through Him and to Him are all things. To Him be the glory forever. Amen(Rom 11:36)
Clearly, Jesus declared this Himself, from earth,
John 12:32 And I, if I am lifted up from the earth, will draw all men to Myself.”
and from heaven,
Rev 21:5 And He who sits on the throne said, “Behold, I am making all things new.” And He *said, “Write, for these words are faithful and true.” Then He said to me, “It is done. I am the Alpha and the Omega, the beginning and the end".
This unavoidable conclusion led me to investigate the seeming paradoxes between the views of ET/ED/UR by studying the translation issues surrounding “hell/sheol/gehenna”, “olam/aion/age/forever/everlasting”, with the help of writers who had gone before(Jukes, Hanson) and a good lexicon, the resolution of all the seeming objections were resolved.
The keys to unlock the matrix of the wisdom of God, “the mystery”, have always been there- they have just been obscured by the foibles of men. The scriptures, properly translated, taken in full context with one another, provide the Great Resolution 
Eph 1:9-11 In all wisdom and insight He made known to us the mystery of His will, according to His kind intention which He purposed in Him with a view to an administration suitable to the fullness of the times, that is, the gathering together into one of all things in Christ, things in the heavens and things on the earth.
Col 1:19,20 For it was the Father’s good pleasure for all the fullness to dwell in Him, and** through Him to reconcile all things to Himself, having made peace through the blood of His cross; through Him, I say, whether things on earth or things in heaven**.
Eph 4:10 He who descended is Himself also** He who ascended far above all the heavens, so that He might fill all things.**
Whatever the process, whatever the mists obscuring some of the details, 'seen through a glass darkly" or not, the scriptures make it clear that God will become ALL IN ALL, and that this was His plan from the beginning. No true literalist can deny it, once presented with all the evidence.
For the anxious longing of the creation waits eagerly for the revealing of the sons of God. For the creation was subjected to futility, not willingly, but because of Him who subjected it, in hope that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. Rom 8:19-21
For God has shut up all in disobedience so that He may show mercy to all. Rom 11:31
For as in Adam all die, so also in Christ all will be made alive. 1 Cor 15:22