How could Jesus be the firstborn son of God the Father in the Pre-existence when Mormon Canon teaches he is God from Eternity?
2 Nephi 26: 12 And as I spake concerning the convincing of the Jews, that Jesus is the very Christ, it must needs be that the Gentiles be convinced also that Jesus is the Christ, the Eternal God;
Mosiah 3 5 For behold, the time cometh, and is not far distant, that with power, the Lord Omnipotent who reigneth, who was, and is from all eternity to all eternity, shall come down from heaven among the children of men, and shall dwell in a tabernacle of clay, and shall go forth amongst men, working mighty miracles, such as healing the sick, raising the dead, causing the lame to walk, the blind to receive their sight, and the deaf to hear, and curing all manner of diseases.
Alma 11: 44 before the bar of Christ the Son, and God the Father, and the Holy Spirit, which is one Eternal God, to be judged according to their works, whether they be good or whether they be evil.
Doctrine and Covenants 20: 28 Which Father, Son, and Holy Ghost are one God, infinite and eternal, without end. Amen