The Living Christ was... what?

On January 1, 2000, the First Presidency issued a statement titled The Living Christ, which contains the statement: "He was the Great Jehovah of the Old Testament, the Messiah of the New."

I am interested in how other Mormons who have studied theology interpret this confusing statement. I have two issues with it. First, Jehovah is not Christ. However naturally this supposition may seem to Latter-day Saints today, it was not the understanding of Joseph Smith or the early Saints. It is a modern innovation, adopted from the line of thinking that creates the Protestant Trinity, and as far as I know, no revelation has ever been given on it (unless The Living Christ is it!), and it flies in the face of other revelations we have received. Even the Apostle Orson Pratt, who nearly got excommunicated for disagreeing with Brigham Young on the Adam-God issue, believed Jehovah to be the Father:

"God is love," says the Apostle John," and he that dwelleth in love dwelleth in God, and God in him." If, then, this is one of the great attributes of Jehovah, if he is filled with love and compassion towards the children of men, if his son Jesus Christ so loved the world that he gave his life to redeem mankind from the effects of the fall, then, certainly, God the Eternal Father must be in possession of this passion.
--Orson Pratt, November 12, 1876; JD Vol.18, p.288

Charles W. Penrose also agreed:

God, then, the God of the Bible, who is called Jehovah, the person who manifested Himself to Israel as Jehovah, is an individual, a personality, and He made man in His image and His likeness. Now, if we are the children of God, and if Jesus Christ is the Son of God, we can upon that reasoning understand something about what God is like, for there is an eternal principle in heaven and on earth, that every seed begets of its kind, every seed brings forth in its own likeness and character.
--Charles W. Penrose, November 16, 1884; JD Vol.26, p.21

This topic has been covered extensively in articles such as "The Reconstruction of Mormon Doctrine: From Joseph Smith to Progressive Theology" by Thomas G. Alexander which appeared in Sunstone, July-August 1980. Some excerpts from this article are available online. However, as far as I know, this is the first time all fifteen Apostles have put out a signed statement proclaiming this notion, and that is concerning to me.

The second issue is "the Messiah of the New." That seems a preposterous statement to me, as Messiah is a Hebrew word, which is not to be found in the New Testament at all.

The remainder of the document seems theologically sound. My main explanation for this: The Living Christ is a testimony, not a revelation on Theology. There is no reason to expect it to contain accurate theological information when the people writing it have been raised up immersed in a population carrying the same popular understanding of the Godhead as we find in modern LDS literature and not the one given by revelation.