Angels and humans are different kinds of created beings. Elijah & Enoch are human beings that were taken to heaven.
Humans taken to heaven are still humans but have been totally transformed (without sin)... such as will happen at the first resurrection.
The phrase “without father or mother” was also employed to describe orphans, illegitimate children, or persons whose origin was unknown. So the phrase by itself does not prove that Melchizedek was divine.
Melchizedek is not eternal in his own right, but in the narrative Melchizedek is
made to resemble the Son of God, the only one who truly remains priest forever. Melchizedek is like Christ in the sense that Scripture does not provide any record of his birth, his genealogy, or his death. That absence of this information in the biblical account is used by the apostle to liken Melchizedek to Christ, who is indeed eternal.
The two witnesses ....
The two witnesses represent the Bible – both Old and New Testaments. The two cannot be separated. God’s people are called to proclaim the full Bible message to the world – “the whole counsel of God”
(Acts 20:27, NKJV).
The witnesses are pictured as prophesying in sackcloth during the prophetic period of 1,260 days/years (A.D. 538-1798). Sackcloth is the garment of mourning
(Gen. 37:34); it points to the difficult time when the truths of the Bible were buried, and covered over, by human traditions.
It is the Word of God that bears witness (testament of Jesus) ... not human beings (we are faulty) ... the Word of God is not.
John 5:39-44 NKJV
You search the Scriptures, for in them you think you have eternal life; and
these are they which testify of Me.