In the Bible, "lucifer" was not a person. It was just a word
used to describe the proud king of Babylon.
In Isaiah 14:12 the term 'lucifer' is Latin for "light bearer"
(a translation of the Hebrew 'hehlel' meaning 'shining one' ). The
term is also used concerning the Mazzaroth constellation
(translated 'luciferum' in Latin(Job 38:32footnote) .
Many have come to feel that this word is a name of Satan, but in
actuality it is simply a term used to describe the proud haughty
position taken by Babylon's kings of the line of Nebuchadnezzar.
(Isaiah 14:4-21) A few translations of the Latin Vulgate keep the
word lucifer, making it appear like a name, instead of translating
it into common languages, causing the confusion.
Political powers, kings of the earth, often had alot of Satan's
qualities in their personality and their love of power, so could be
likened to him in many ways (as in the case of the King of Tyre
(Ezekiel 28:11-15). Even Peter, when he inadvertently discouraged
Jesus by his comments was likened to Satan (Matthew 16:23).
As for whether the devil wanted to be 'human and angel'...
The Latin term 'Satan' is a translation of the Hebrew "wesatan"
meaning "resister or opposer", and that's exactly what he is. He
already was an angel, but rejected his God in favor of his own
ideas. All he wants now is, not to BE human, but to have the power
over, and the worship of, humans and to turn people away from the
true God.(Genesis 3:1-5) (Matthew 4:8-10)(Luke 22:31)(Revelation
2:10)