Melchizedek was not a Christophany. That is because Hebrews 7:15 calls Christ "ANOTHER priest" other than Melchizedek - a "SIMILITUDE of Melchizedek". Melchizedek was "made LIKE unto the Son of God" (Hebrews 7:3). That means Melchizedek could not possibly have been Christ Jesus. And Melchizedek was called a MAN in Hebrews 7:4 - so he was not an angelic being either.
Melchizedek, I believe, was another name given to the godly man Enoch who was translated that he should not see death. Enoch did NOT go to heaven after his translation, because Christ said that no man had ascended to heaven yet (as of John 2:13).
Yet Hebrews 7:8 tells us that Melchizedek was still alive on earth as of the time that verse was being written. If Melchizedek actually was the same individual as the translated Enoch, this would explain why the disciples still had the ancient prophesies of Enoch around, which could be included in their written works (such as Jude 14).
Melchizedek the King of Salem, priest of the Most High God, was the lone, solitary example of a translated human individual - made to be the totally unique foundation of the deathless high priesthood order; the pattern for Christ's unique Great High Priesthood, which was also deathless, like Enoch / Melchizedek. There will be no more translated individuals such as Enoch / Melchizedek - scripture makes no such promise, as all others except that one case of Enoch / Melchizedek are appointed to die the one time (Hebrews 9:27-28), just as Christ died the one time for us.
Melchizedek is said to be a priest, but does that mean high priest? As well as Melchizedekian priesthood is spoken of as an order, as the sons of Aaron are an order. So, not all priests, are sons of Aaron, not all priests are high priests. But I am thinking along the same lines as you ( the fathers of Abraham) which were prophets (which are annointed ones; i.e. christs)
Three annointed ones
kings, highpriests, prophets.
Levitical priests were also the messenger (angel) of the Lord.
Mal 2:4 And ye shall know that I have sent this commandment unto you, that my covenant might be with Levi, saith the LORD of hosts.
5 My covenant was with him of life and peace; and I gave them to him for the fear wherewith he feared me, and was afraid before my name.
6 The law of truth was in his mouth, and iniquity was not found in his lips: he walked with me in peace and equity, and did turn many away from iniquity.
7 For
the priest’s lips should keep knowledge, and they should seek the law at his mouth: for he is the messenger of the LORD of hosts.
John the baptist, Priest a messenger (angel)
Mal 3:1 ¶ Behold, I will send my messenger, and he shall prepare the way before me: and the Lord, whom ye seek, shall suddenly come to his temple, even the messenger of the covenant, whom ye delight in: behold, he shall come, saith the LORD of hosts.
2 But who may abide the day of his coming? and who shall stand when he appeareth? for he is
like a refiner’s fire, and like fullers’ soap:
3 And he shall sit as a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the LORD an offering in righteousness.
4 Then shall the offering of Judah and Jerusalem be pleasant unto the LORD, as in the days of old, and as in former years.
To much emphasis on the nation of Israel, not enough on the priesthood, and John's ministry...in fulfilling the law IMO