Do you believe he was the highest angel in heaven before the creation of earth and man?
Since creation followed the sequence given in Genesis 1 and 2, it is likely that the angels were created on the 4th day, when the stars were also created (angels are often called stars and vice versa). So Lucifer -- a cherub -- was created after the earth and before man.
However, it is purely your assumption that the seraphim rank higher than the cherubim. If anything the cherubim are the ones who support the throne of God so they could be on an equal footing with the seraphim.
But the archangels would be the highest ranking. In any event, Satan (formerly Lucifer) is the highest ranking angel among all the evil angels (Rev 12) and he is the one who disputed with Michael the archangel regarding the body of Moses (Jude 1), as well as the standing of Joshua the high priest before God (Zech 3). The Hebrew
ha Satan means "Adversary" and this is the chief adversary of God and man.