Interesting thoughts you have - sent me scurrying to my Bible for context .
Isn't there a bit of a problem putting good and evil beside each other, implying they are more equal in quality than they are? I mean, Jesus said, 'only God is good', and He also had said, 'I create evil'. Jesus had to partake of 'the likeness of sinful flesh' - the lowest common denominator - to show us that we could overcome evil, with divine help (Romans 8:13), but how many humans truly want to be god-like in the way that Jesus was?
I think you've take rather a liberty with the 'all in all' in 1 Cor 12, as it is strictly limited to the operation of the gifts of the Holy Spirit through Christian believers. The 'all in all', is: the same God in each believer acting through the different gifts He has distributed within the Church.
1 Corinthians 12:1 Now concerning spiritual [gifts], brethren, I would not have you ignorant. 2 Ye know that ye were Gentiles, carried away unto these dumb idols, even as ye were led. 3 Wherefore I give you to understand, that no man speaking by the Spirit of God calleth Jesus accursed: and [that] no man can say that Jesus is the Lord, but by the Holy Ghost. 4 Now there are diversities of gifts, but the same Spirit. 5 And there are differences of administrations, but the same Lord. 6 And there are diversities of operations, but it is the same God which worketh all in all. 7 But the manifestation of the Spirit is given to every man to profit withal.
Likewise, in Ephesians 1:15 onwards, Paul is talking about Christ in the Church; it's one very long sentence, according to Green's Literal.
15 Because of this, hearing of your faith in the Lord Jesus and love toward all the saints, 16 I also do not cease giving thanks on your behalf, making mention of you in my prayers, 17 that the God of our Lord Jesus Christ, the Father of glory, may give to you a spirit of wisdom and revelation in the full knowledge of Him, 18 the eyes of your mind having been enlightened, for you to know what is the hope of His calling, and what are the riches of the glory of His inheritance in the saints, 19 and what is the surpassing greatness of His power toward us, the ones believing according to the working of His mighty strength 20 which He worked in Christ in raising Him from the dead; yea, He seated Him at His right hand in the heavenlies, 21 far above all rule, and authority, and power, and lordship, and every name having been named, not only in this age, but also in the coming age; 22 and He "put all things under His feet" and gave Him to be Head over all things to the assembly, 23 which is His body: the fullness of the One filling all things in all; 2:1 and you being dead in deviations and sins, 2 in which you formerly walked according to the course of this world, according to the ruler of the authority of the air, the spirit now working in the sons of disobedience, 3 among whom we also all conducted ourselves in times past in the lusts of our flesh, doing the things willed of the flesh and of the understanding, and were by nature the children of wrath, even as the rest.
Surely, these demonstrate that the Unity in God is limited to those domains over which He has complete dominion, graciously including all the creatures who choose to come into agreement with the terms He has established for koinonia with Himself?
John 15:5 I am the Vine; you are the branches. The one abiding in Me, and I in him, this one bears much fruit, because apart from Me you are not able to execute, nothing. 6 Unless one remains in Me, he is cast out as the branch and is dried up; and they gather and throw them into a fire, and they are burned. 7 If you remain in Me, and My Words remain in you, whatever you desire you will ask, and it shall happen to you. 8 In this My Father is glorified, that you should bear much fruit; and you will be disciples to Me. 9 As the Father loved Me, I also loved you; continue in My love. 10 If you keep My commandments you will continue in My love, as I have kept My Father's commandments and continue in His love. 11 I have spoken these things to you that My joy may abide in you, and your joy may be full. 12 This is My commandment, that you love one another as I loved you. 13 Greater love than this has no one, that anyone should lay down his soul for his friends. 14 You are My friends if you do whatever I command you. 15 I no longer call you slaves, for the slave does not know what his lord does. But I called you friends, because all things which I heard from My Father I made known to you. 16 You have not chosen Me, but I chose you out and planted you, that you should go and should bear fruit, and your fruit remain, that whatever you should ask the Father in My name, He may give you. 17 These things I command you, that you love one another.
Clearly, God is most desirous of Unity, but not at the expense of authentic wholeness or perfection (completion).
Ephesians 3:14 For this cause I bow my knees unto the Father of our Lord Jesus Christ, 15 of whom the whole family in heaven and earth is named, 16 that he would grant you, according to the riches of his glory, to be strengthened with might by his Spirit in the inner man; 17 that Christ may dwell in your hearts by faith; that ye, being rooted and grounded in love, 18 May be able to comprehend with all saints what [is] the breadth, and length, and depth, and height; 19 and to know the love of Christ, which passeth knowledge, that ye might be filled with all the fulness of God.
20 Now unto him that is able to do exceeding abundantly above all that we ask or think, according to the power that worketh in us, 21 unto him [be] glory in the church by Christ Jesus throughout all ages, world without end. Amen. 4:1 I therefore, the prisoner of the Lord, beseech you that ye walk worthy of the vocation wherewith ye are called, 2 with all lowliness and meekness, with longsuffering, forbearing one another in love; 3 endeavouring to keep the unity of the Spirit in the bond of peace. 4 [there is] one body, and one Spirit, even as ye are called in one hope of your calling; 5 one Lord, one faith, one baptism, 6 one God and Father of all, who [is] above all, and through all, and in you all. 7 But unto every one of us is given grace according to the measure of the gift of Christ.
16 That he would grant you, according to the riches of his glory, to be strengthened with might by his Spirit in the inner man; 17 That Christ may dwell in your hearts by faith; that ye, being rooted and grounded in love, 18 May be able to comprehend with all saints what is the breadth, and length, and depth, and height; 19 And to know the love of Christ, which passeth knowledge, that ye might be filled with all the fulness of God.