This may be helpful to you; or for your notes or whatever.
I see what Gert is saying when he says heylel as morning star but what he is saying is'nt reason to say that heylel correctly translated is morning star. If the correct translation in this instance were to merely be morning star (boqer kokab) would have been used. Further; some of my research seems to indicate (despite what all these "bible dictionaries" say) - at this time - that the word heylel is meant as soldier; bright soldier; or leader of soldiers. Could be another reason (other than the meaning of the parts which make up the word lucifer)-(which is translated from heylel), that some people regard lucifer him or it-self as something good. In the context of the Isaiah lines though; it seems to be refering to something or someone (or a personified something) that once was good which turned egotistical and fell from heaven.