The word melek in Hebrew simply means "king". This is almost too generic to be of any value.
The second part of the name, -or, could perhaps derive from Har (Egyptian Horus), who was worshipped as a god of light, but this was hardly unique. Almost every god was linked to the sun. The root -or- is also related to "gold".
There was also a Persian king, Artaxerxes, who was called Macro-cheir, meaning "long hand" in Greek. He is depicted with a very large/strong right hand.
A Greek name for the god Horus the Elder was Cheiron, meaning "hand". In Hebrew, the name Judah also derives from a word meaning "hand". So, the epithet of Artaxerxes typecasts him both as a Judah figure and as a Benjamin, which means "son of the right/strong hand". In Egyptian mythology, Horus the Younger (Benjamin) was the true son of Horus the Elder (Judah), whom he had sired on behalf of his dead brother Osiris (Issachar).
So, it is at least possible that Melchior should be associated with the Michael/Judah type. However, this should be researched further to gain more confidence.
The name Melchizedek, "righteous king", is an epithet deriving from the god Ptah (archetypal "Joseph").
© Charles N. Pope, US Library of Congress. All rights reserved.