Ellen White and "the eternal, self-existing Son" quotation

Just about any SDA Trintarian who quotes Ellen White to "prove" their position will reference the book "Evangelism."  In order to support the supposition that Christ was NOT begotten of His Father in eternity, many will quote that Christ "is the eternal, self-existing Son" of God.  I will not undertake to interpret Mrs. White's intended meaning of the phrase one way or the other.  While researching EGW's source material for my recent blog, I discovered the following example of another paraphrased statement "borrowed" from a Trinitarian author.  This single EGW quotation is referenced so often, and as having so much theological weight of argument, it is of special interest WHO she copied from.  The point to be made, is NOT an indictment of plagiarism, or literary copying; but rather the notable absence of Trinitarian terminology in her overall writings even while relying (sometimes heavily) upon the writings of Trinitarian authors.  We begin first with the Ellen White Quote:

Not one of the angels could have become surety for the human race: their life is God's; they could not surrender it. The angels all wear the yoke of obedience. They are the appointed messengers of Him who is the commander of all heaven. But Christ is equal with God, infinite and omnipotent. He could pay the ransom for man's freedom. He is the eternal, self-existing Son, on whom no yoke had come; and when God asked, "Whom shall I send?" he could reply, "Here am I; send me." He could pledge himself to become man's surety; for he could say that which the highest angel could not say,--I have power over my own life, "power to lay it down, and . . . power to take it again." {Ellen G. White, YI, June 21, 1900 par. 2; Evangelism 615; 12MR 394.3}

(Memories of Olivet, by J. R MACDUFF, D.D.[Presbyterian Minister],1868, p.93)
Jesus, our adorable Saviour, had the yoke of no obligation laid upon Him, in undertaking the great work of atonement. The Infinite, the Independent, the Omnipotent, He was beyond and above all law—all the requirements of creatureship : He was " a law unto Himself." Of the highest created angels it could not be said, " upon which never came yoke." They have the yoke of dependence laid upon them—the yoke of duty common to all God's family. They are the servants—the delegated messengers of Him before whom they cast their crowns; and as such, even had they been willing for the self-sacrifice, and had that sacrifice been in other respects adequate and admissible, they could, by no personal act, have surrendered their lives as a ransom for the guilty. By attempting to do so, though the expression is a strong one, they would virtually have been suicides: they would have been guilty of forfeiting that which was not their own, and for which they were responsible to another. On Christ—the Eternal, Self-existent Son, alone, had there come no yoke. He alone was free to undertake the Suretyship of the fallen. When the question was propounded amid the heavenly hierarchies, " Whom shall I send, and who will go for us?" He alone of the myriad throng was warranted to reply, " Here am I, send me:" He alone could assert, (what neither angel nor seraph could do,) "  I have power over my own life: I have power to lay it down, and I have power to take it again,"