Of course Jesus said he seen Abraham and Melchizedek did see Abraham. Only two persons in the Bible hold both a King and Priest, titles
John 8: 56 Your father Abraham rejoiced to see my day: and he saw it, and was glad. 57Then said the Jews unto him, Thou art not yet fifty years old, and hast thou seen Abraham? 58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.
Genesis 14:18 And Melchizedek king of Salem brought forth bread and wine: and he was the priest of the most high God. 19 And he blessed him, and said, Blessed be Abram of the most high God, possessor of heaven and earth: 20 And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all.
4 The LORD hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek.
Zechariah 6: 13 Even he shall build the temple of the LORD; and he shall bear the glory, and shall sit and rule upon his throne; and he shall be a priest upon his throne: and the counsel of peace shall be between them both.
6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. 7 Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even forever. The zeal of the LORD of hosts will perform this.
1 For this Melchisedec, king of Salem, priest of the most high God, who met Abraham returning from the slaughter of the kings, and blessed him; 2 To whom also Abraham gave a tenth part of all; first being by interpretation King of righteousness, and after that also King of Salem, which is, King of peace; 3 Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually.
The Mormons have reinvented a whole different Melchezedek