What basis do you have for this classification of "local" and "private"? No one calls EGW scripture, but all prophets have a message from God, that is the point.
Public Revelation is what's in Sacred Scripture & Sacred Tradition - and that closed out with the death of the last Apostle. This is why we have Scripture that we "quote" & sometimes refer to Sacred Tradition. Daniel, Isaiah, etc. were Biblical Prophets - they're Revelations were "Public" (for everyone).
A "Local Prophet's" authority terminates at their death - their revelations don't have a bearing on anyone or anything outside their influence while they are alive and certainly don't have "continuing authority" after their death. Only Canonical Prophets have continuing authority. Below is an example of why its not a good idea to give "continuing authority" to a prophet that had already failed the test of being a true prophet.
Canonical or Public Prophets ALWAYS confirm established "existing" doctrine - Public or Canonical Prophets NEVER MUTATE Doctrine so that it becomes the direct opposite of what it was. Take for example the Sacrifice of Christ on the Cross - it was PERFECT and was indeed the Atonement spoken of by the Old Testament Prophets. Below are two examples of "mutations of doctrines" that Ellen White endorsed with her writings and visions. Again, what Ellen taught in the below areas WASN'T development of Doctrine - it was mutation of Doctrine.
1. Rejection in the Doctrine of the Atonement
“Another error, even more generally endorsed than any of the foregoing, is the doctrine of the atonement on the cross. This also furnishes another support for Unitarianism. The Scriptures plainly teach that Christ died for all men. Now if his death on the cross was the atonement, then the sins of all men are atoned for, and all will be saved. The conclusion is unavoidable, and we deny the doctrine of the atonement on the cross, not because it leads to this belief, but because it is scripturally untrue, and then as an incentive for proclaiming its falsity we have the fact that it is a strong pillar for a destructive error.” Sabbath Herald, August 29, 1865 No. 13.
2. Mutation Capable Creature Christ that could have sinned & eternally lost Salvation for Himself & eternally passed out of existence.
Ellen White, Sabbath Herald, Jan 14, 1909
"We are to be partakers of knowledge. As I have seen pictures representing Satan coming to Christ in the wilderness of temptation in the form of a hideous monster, I have thought, How little the artists knew of the Bible! Before his fall, Satan was, next to Christ, the highest ANGEL in heaven."
Ellen White Desire of Ages page 49
Satan in heaven had hated Christ for His position in the courts of God. He hated Him the more when he himself was dethroned. He hated Him who pledged Himself to redeem a race of sinners. Yet into the world where Satan claimed dominion God permitted His Son to come, a helpless babe, subject to the weakness of humanity. He permitted Him to meet life's peril in common with every human soul, to fight the battle as every child of humanity must fight it, at the risk of failure and eternal loss.”
Ellen White, L5,1900 SDA BC Volume 7,page 926
He became subject to temptation, endangering as it were, HIS DIVINE attributes. Satan sought, by the constant and curious devices of his cunning, to make Christ yield to temptation
Ellen White MS 99,1903 page 3,4
He had infinite power ONLY because He was perfectly obedient to His Father's will
Ellen White, DA 131
Then as the glories of the eternal home burst upon our enraptured senses we shall remember that Jesus left all this for us, that He not ONLY became an exile from the heavenly courts, but for us took the risk of failure AND eternal loss
Ellen White, GCB Dec 1, 1895
Remember that Christ risked all; "tempted like as we are," he staked EVEN his own eternal existence upon the issue of the conflict. Heaven itself was imperiled for our redemption.
Ellen White, SM book 1, page 256
Could Satan in the least particular have tempted Christ to sin, he would have bruised the Saviour's head. As it was, he could only touch His heel. Had the head of Christ been touched, the hope of the human race would have perished. Divine wrath would have come upon Christ as it came upon Adam. Christ and the church would have been without hope.”
Ellen White, SDA GBC 1 Dec 1895
Remember that Christ risked all; "tempted like as we are," he staked even his own eternal existence upon the issue of the conflict. Heaven itself was imperiled for our redemption. At the foot of the cross, remembering that for one sinner Jesus would have yielded up his life, we may estimate the value of a soul
3. The Doctrine of the Trinity as Catholic's, Lutherans, Baptists, Methodist's, Eastern Orthodox Christians understand it - i.e. Adventist groups reject the Nicene Creed as Babylon and a departure from what the Bible teaches.
James White ( Ellen's husband )
"We invite all to compare THE TESTIMONIES of the Holy Spirit THROUGH Mrs. White with the word of God. And in this we do not invite you to compare them with your creed. That is quite another thing. The TRINITARIAN may compare them with his creed, and because THEY DO NOT AGREE WITH IT, CONDEMN them [ the testimonies of Mrs. White ]. The Adventist Review & Sabbath Herald June 13, 1871
4. The Father or Father God has eternally had a flesh hominid body complete "with all the members and parts of a perfect man". Both Michael and Lucifer the archangels also possessed hominid flesh bodies with organs and parts prior to the Incarnation of Michael the archangel. This Doctrine was called "THE PERSONALITY OF GOD".
Sabbath Herald October 8, 1903
OF late the question has repeatedly come to me, Does it make any real difference whether we believe in the personality of God, as long as we believe in God? My answer invariably is, It depends altogether upon the standpoint from which we view it. If from the Spiritualist's, -the Christian Scientist's, the Universalist's, or if from the standpoint of any other " ist" or " ism," it makes but little or no difference. But from the standpoint of Seventh-day Adventists it makes all the difference in the world. Second^ At the creation God said to Christ, " Let us make man in our image, after our likeness. ... So God created man in his own image, in the image of God created he him; male and female created he them." Gen. 1: 26, 27. Man bore the image of God both morally and physically; for -after man sinned, we 'read'that Adam "begat a son in his own likeness, after his image; and called his name Seth." Gen. 5:3. Here is an explanation of the words " image " and "- likeness." As Seth bore both the physical and the moral nature of Adam, so Adam bore the physical and the moral likeness of God.Neither was this image of God which man bore a mere concept; for the Bible declares that the Lord has parts, the same as the human body. Therefore we repeat what we previously said, To deny the personality of God, is to deny the existence of the sanctuary in the heavens; for there God dwells. It is to deny the existence of the angels; for they are his throne. It is to deny' the law of God; for it is the foundation of his throne. It is to deny the existence of Satan; for he is a fallen angel
Sabbath Herald Oct 8,1903
"The doctrine of the Personality of God IS the fundamental doctrine of the Scriptures..."
...""NEITHER was this image of God a mere concept; FOR the Bible declares that the Lord has PARTS, THE SAME AS the human body"."OUR EXISTENCE as a people is FOUNDED on a belief in the truths stated above".