According to the Bible, the first man was Adam (1 Cor 15:45). Since Adam was the first man and Lucifer (Satan) was in the Garden of Eden when Adam and Eve were deceived, then the answer to your first question must be, no, he was never a man.
The Bible implies that angels have always been angels (Hebrews 1-2) but angels of God can appear as men (Genesis 19, Hebrews 13:2). The Devil has his angels (which fell with him and are called Demons), and God has His angels who were not deceived by Satan. They are at war with each other (Daniel 10).
The Bible does recognize that Satan can possess men, and as such refers to Satan as a man in the prophecies of Isaiah 14:16, where in context, the prophecy seems to deal with a spiritual being (Satan) and a ruler of a country (possessed ruler). I have included the verses from Isaiah 14 and Ezekiel 28 that talk about the fall of Satan from the throne of God. These passages teach that Satan/Lucifer was created as an angel, became proud, rebelled against God and fell from heaven.
Isa 14:12 "How you are fallen from heaven, O Lucifer, son of the morning! How you are cut down to the ground, you who weakened the nations! 13 For you have said in your heart: 'I will ascend into heaven, I will exalt my throne above the stars of God; I will also sit on the mount of the congregation on the farthest sides of the north; 14 I will ascend above the heights of the clouds, I will be like the Most High.' 15 Yet you shall be brought down to Sheol, to the lowest depths of the Pit. 16 "Those who see you will gaze at you, and consider you, saying: 'Is this the man who made the earth tremble, who shook kingdoms, [I think this is referring to the last day’s Antichrist who will be possessed by Satan himself (Revelation 13:2) and killed by Jesus at the second coming] (NKJ)
Ezek 28:12 "Son of man, take up a lamentation for the king of Tyre [The King of Tyre was a man, but apparently he was possessed by Satan since the following words of the prophecy cannot be addressing just the man], and say to him, 'Thus says the Lord GOD: "You were the seal of perfection, full of wisdom and perfect in beauty. 13 You were in Eden, the garden of God; every precious stone was your covering: the sardius, topaz, and diamond, Beryl, onyx, and jasper, sapphire, turquoise, and emerald with gold. The workmanship of your timbrels and pipes was prepared for you on the day you were created. 14 "You were the anointed cherub who covers; I established you; you were on the holy mountain of God; you walked back and forth in the midst of fiery stones. 15 You were perfect in your ways from the day you were created, till iniquity was found in you. 16 "By the abundance of your trading you became filled with violence within, and you sinned; therefore I cast you as a profane thing out of the mountain of God; and I destroyed you, O covering cherub, from the midst of the fiery stones. 17 "Your heart was lifted up because of your beauty; you corrupted your wisdom for the sake of your splendor; I cast you to the ground, I laid you before kings, that they might gaze at you. 18 "You defiled your sanctuaries by the multitude of your iniquities, by the iniquity of your trading; therefore I brought fire from your midst; it devoured you, and I turned you to ashes upon the earth in the sight of all who saw you. 19 All who knew you among the peoples are astonished at you; you have become a horror, and shall be no more forever."' " (NKJ)
In Summary, Satan was created as an angel; fell from heaven (in verses above and in Luke 10:17-18), but still has access to heaven (Job 1 and 2). He accuses us before God daily (Revelation 12:10) until the battle in heaven forever casts him out of heaven and down to the earth during the tribulation period (Revelation 12).
Satan will then have a short time to possess the Antichrist and through him try to destroy all the people of God. He fails to complete this mission when the Lord Jesus returns, kills the Antichrist and sends the Devil Satan into the bottomless pit for 1,000 years.
Then the Devil will be released to have one more chance to deceive those who have been born during the 1,000-year reign of Christ on Earth. God then defeats Satan and those who followed his lies and throws Satan into the Lake of Fire forever and ever. (Revelation 19-20)