What is the role of Lucifer in the Heavenly realm? Lucifer means "bearer of light". Would this means that he bear Jesus who revealed himself as the Light or the scriptures are speaking of a different light?

Scriptures, Church Fathers and Saints teach that Lucifer is only a "cherub" but Book of Ezekiel chapter 28 described the beauty and intelligence of Lucifer plus mentioned that he was "anointed" (Ezekiel 28:14)


  Thou [art] the anointed cherub that covereth


What is the role of Lucifer in the heavenly realms before his fall according to Catholicism?

Does the anointing given to him means additional role aside from bearing the light?

It may appear that I am inquiring numerous question, but the intention is simply to have a clear picture of the totality of Lucifer's role in the heavenly realm before his fall.
What is the role of Lucifer in the Heavenly realm?

First of all, the Church Fathers do not believe that the name of Lucifer is the proper name of the Devil. However in Catholic tradition the Devil has many names including Lucifer.

In any case this question deals with much speculation since the Church has yet to pronounce on anything concerning this subject in a definitive manner.


  The name Lucifer originally denotes the planet Venus, emphasizing its brilliance. The Vulgate employs the word also for "the light of the morning" (Job 11:17), "the signs of the zodiac" (Job 38:32), and "the aurora" (Psalm 109:3). Metaphorically, the word is applied to the King of Babylon (Isaiah 14:12) as preeminent among the princes of his time; to the high priest Simon son of Onias (Ecclesiasticus 50:6), for his surpassing virtue, to the glory of heaven (Apocalypse 2:28), by reason of its excellency; finally to Jesus Christ himself (2 Peter 1:19; Apocalypse 22:16; the "Exultet" of Holy Saturday) the true light of our spiritual life.
  
  The Syriac version and the version of Aquila derive the Hebrew noun helel from the verb yalal, "to lament"; St. Jerome agrees with them (In Isaiah 1.14), and makes Lucifer the name of the principal fallen angel who must lament the loss of his original glory bright as the morning star. In Christian tradition this meaning of Lucifer has prevailed; the Fathers maintain that Lucifer is not the proper name of the devil, but denotes only the state from which he has fallen (Petavius, De Angelis, III, iii, 4). - Lucifer (Catholic Encyclopaedia)


As for what the Devil did in the Heavenly Realm, the Catholic Encyclopaedia) may have at least a partial answer.


  The language of the prophets (Isaiah 14; Ezekiel 28) would seem to show that Lucifer held a very high rank in the heavenly hierarchy. And, accordingly, we find many theologians maintaining that before his fall he was the foremost of all the angels. Suarez is disposed to admit that he was the highest negatively, i.e. that no one was higher, though many may have been his equals. But here again we are in the region of pious opinions, for some divines maintain that, far from being first of all, he did not belong to one of the highest choirs - Seraphim, Cherubim, and Thrones--but to one of the lower orders of angels. In any case it appears that he holds a certain sovereignty over those who followed him in his rebellion. For we read of "the Devil and his angels" (Matthew 25:41), "the dragon and his angels" (Apocalypse 12:7), "Beelzebub, the prince of devils"--which, whatever be the interpretation of the name, clearly refers to Satan, as appears from the context: "And if Satan also be divided against himself, how shall his kingdom stand? Because you say that through Beelzebub I cast out devils" (Luke 11:15, 18), and "the prince of the Powers of this air" (Ephesians 2:2). At first sight it may seem strange that there should be any order or subordination amongst those rebellious spirits, and that those who rose against their Maker should obey one of their own fellows who had led them to destruction. And the analogy of similar movements among men might suggest that the rebellion would be likely to issue in anarchy and division. But it must be remembered that the fall of the angels did not impair their natural powers, that Lucifer still retained the gifts that enabled him to influence his brethren before their fall, and that their superior intelligence would show them that they could achieve more success and do more harm to others by unity and organization than by independence and division.
  
  There is no need to discuss the view of some theologians who surmise that Lucifer was one of the angels who ruled and administered the heavenly bodies, and that this planet was committed to his care. For in any case the sovereignty with which these texts are primarily concerned is but the rude right of conquest and the power of evil influence. His sway began by his victory over our first parents, who, yielding to his suggestions, were brought under his bondage. All sinners who do his will become in so far his servants. For, as St. Gregory says, he is the head of all the wicked--"Surely the Devil is the head of all the wicked; and of this head all the wicked are members" (Certe iniquorum omnium caput diabolus est; et hujus capitis membra sunt omnes iniqui.--Hom. 16, in Evangel.). This headship over the wicked, as St. Thomas is careful to explain, differs widely from Christ's headship over the Church, inasmuch as Satan is only head by outward government and not also, as Christ is, by inward, life-giving influence (Summa III:8:7).


The following articles may be of interest:


Is Satan a seraph or a cherub?
Biagio da Cesena: “Pope Paul III joked that his jurisdiction did not extend to hell!”
Angels: From the Teachings of Saint Thomas Aquinas