Those are good points, but remember that I am only speaking for literal interpretation of the Bible. I don't have the time to list all the etymological technicalities, but "Satan" is really a phonetic recovery of the original Hebrew and Aramaic forms of "devil", though that name, of course, refers to the devil rather than a devil. "Lucifer" was used extensively by the apostle Paul, and is also the name used in what I take to be an account of the fall of the Devil (also desribing the fate of a wicked Assyrian king) in Isaiah 12:
"How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: I will ascend above the heights of the clouds; I will be like the most High. Yet thou shalt be brought down to hell, to the sides of the pit. They that see thee shall narrowly look upon thee, and consider thee, saying, Is this the man that made the earth to tremble, that did shake kingdoms; That made the world as a wilderness, and destroyed the cities thereof; that opened not the house of his prisoners? All the kings of the nations, even all of them, lie in glory, every one in his own house. But thou art cast out of thy grave like an abominable branch, and as the raiment of those that are slain, thrust through with a sword, that go down to the stones of the pit; as a carcase trodden under feet." (verses 12-19)
"Beelzebub" has its origin in a Hebrew parody of the proper name for the Philistine god "Baal-zebub" ("Lord of the fly") worshipped at a place called Ekron according to one Old Testament account. This and other facts I don't really have time to list seem to support the idea that the three are simply different names for the same person.
On your second question, angels can (and according to biblical accounts, have) taken on forms. Gabriel and Michael (the two angels other than Lucifer who are mentioned by name in the Bible) are both mentioned as being seen by members of the human race. By the bye, these forms are always masculine, contrary to popular belief. However the only angels I can think of now (though there may be other examples that don't come to mind right now) to be described as winged and humanoid are the seraphims in the book of Ezekiel, and the two images of cherubims with outstretched wings covering the mercy seat of the Ark of the Covenant.
I don't have time to get into detail (nor would anyone else on the forums care for me to do so, I think), but if you would like to continue this discussion through personal messages, I'll be online again tomorrow.
