You are right that the story in Revelation 12 is paralleled somewhat in the much earlier Eblaite text, tho by viewing the Semitic conflict myth through a Christianizing lens (e.g. stipulating an "original conflict" for the myth and by reading "Satan" into the text) you run the risk of distorting the meaning and purpose of these texts. Again, we are dealing with the primeval chaos of the "watery deeps" (tiahamatim), restrained and defeated through creation and divine power, and not a Christian notion of a "rebel" or renegade angel. Indeed, when you look at the legends of Enlil, Marduk, Zeus, and especially Baal, it is the storm-god who revolts and unseats the Sea/Deep as the reigning god. In the Enuma Elish, Tiamat is something of a tyrant who is attacked by Marduk (= Enlil) in a rebellion. Yamm is El's "beloved son" that the nasty upstart Baal (=Yahweh in Israelite mythology) decides to attack and unseat as king. In reality, there are a number of different conflicts in Canaanite mythology involving El, Baal, and Anat in different roles as protagonists, defeating different mythological enemies. You would like to view the conflict as something that happened in a rebellion of Satan after God created the cosmos, but the primary result of the conflict is Creation itself -- Creation occurred through such a conflict between the creator-god and the chaos entity, yet the conflict is also part of competition in the divine pantheon. The conflict with Baal-Hadad and Yamm is an example of this. The texts in Isaiah 14 and Ezekiel 28 draw directly on this mythological context, and confusedly mix and combine motifs refering to different deities to refer to one particular rebel deity in particular. Thus the morning-star god Shahar being named, but through the name of his son Helal, and whose fall really that of another morning-star god, Athtar. Clearly the biblical use of older myths is a secondary use. It is the same with Revelation. Although the chaos monster is named as Satan the Devil, theologically an angel being within Jewish apocalyptic writing (i.e. Satan'el), the original motif of the monster as embodying the Sea is still latent in the text. I know of no reputable scholar who studies Near Eastern conflict myths claim that the biblical version is original, when so much evidence is against it. Please see GOD'S CONFLICT WITH THE DRAGON AND THE SEA: ECHOES OF A CANAANITE MYTH IN THE OLD TESTAMENT by John Day (Cambridge: University Press, 1985), which gives a complete discussion on the evidence of the biblical dependence on older pagan myths, and their use in the NT. Especially please see chapter 4, "The eschatologization of the divine conflict with the dragon and the sea," which shows how the original myth was altered in Daniel and Revelation.
The astral imagery in the Eblaite story is quite striking, and reminiscent of Revelation. I know of no biblical evidence that Jesus or Michael was solarized; instead, Jesus is linked to the morning star in Revelation (which is interesting considering the mythological background of the morning star in Isaiah with Shahar and Athtar). The other mythological battles of the Near East are either not located in terms of space (as heaven proper and the earth were not yet created at the time of the battle), or were located on the heavenly mountain (think in terms of Mount Olympus or Mount Casius). The descent of Habhaby to the "earth" is reminiscent of Revelation, but don't miss the point: the astral waters like the heavenly waters of Tiamat and Apsu in Babylonian mythology is confined to the earth to a specific location and placed within boundaries (creating the earthly "Sea"). And in Revelation, this is exactly what the Dragon does: he vomits water and forms a sea (from which other beasts arise). It is thus significant that in the Eblaite version, the word used for the "watery deep" of Habhaby is tihamatim, the plural cognate of Tiamat -- out of whose corpse Marduk created the heavens and the earth. The theme of "binding" the monster is exactly that in Psalm 33:7-8, Proverbs 8:24, 27-29, Jeremiah 5:22, Genesis 1:9, and especially Job 38:8-11 in which God "shut in the Sea with doors ... and shut it within its bonds and set bars and doors". The doors are both mentioned in Job and the Eblaite text, and there is another link in Isaiah 26:20 which mentions hby (reminiscent of Ugaritic hby, Eblaite Habhaby; in each case the "h" is really heth) in connection with ktib dltyk "your double-doors" -- the same word that occurs in the Eblaite myth (daltan "double doors"). The other important thing to note is that the "earth" to which the serpent is "confined" is Eblaite ars [arets], which in Hebrew refers to the "land" but in Ugaritic refers to the "underworld". So we may also have a motif here of an heavenly deity being thrown down to the underworld, which is just what we find in the Rig Veda concerning Vrtra, and in Isaiah 14.
