Above are the many trinity/godhead/heavenly trio books I carefully studied, over time, to make sure I was not missing any important facts in my research on this very important topic.

I was amazed at the lack of actual biblical support or Ellen G. White support, contained in the majority of these books, in relation to the trinity doctrine ... with the exception of the book by Regan Leader called "Exploring the True God," which does not support the trinity doctrine, but rather stands upon a plain "thus saith the LORD".

The heavenly Trio mentioned by Ellen G. White is a simple, yet profound, truth that is easily understood when you are not influenced by the mystery trinity doctrine, which only appeared in Christian history around 325 AD to 381 AD and later.  The heavenly Trio is composed of ... One God, the Father, of whom are all things; One Lord Jesus Christ, by whom are all things; and One Spirit, the omnipresent Spirit & Life of God and of Christ. God the Father (who is all the fulness of the godhead bodily) and His divine only begotten Son (who is all the fulness of the godhead manifested) are one in mind, spirit, nature, character, and purpose. Ellen G. White states plainly, "We want the Holy Spirit, which is Jesus Christ." (the Spirit that comes in all the fulness of the godhead, making manifest the power of God's grace). "This refers to the omnipresence of the Spirit of Christ, called the Comforter." The man Christ Jesus is represented on earth and throughout the universe by His own omnipresent Spirit—the Spirit of Christ, called the Comforter. Jesus is our Comforter both as a human being and as a divine being. While Jesus is in heaven, cumbered with the personality of humanity, He is also with us now, dwelling in our hearts, divested of the personality of humanity, by the indwelling presence of His own divine representative omnipresent Spirit, a spiritual manifestation, which is not outwardly visible to the world. Christ in you, the hope of glory.