So with all of the power of the Elohim and their divine origin, do you think it's possible for them to 'mantle', using the Elder Scrolls term, Yahweh and break their own shackles and ascend to Godhood?

I would assume it would take a combination of Faith, such as a considerable cult, and knowledge of Lore.

Possible. I mean, if Mages can ascent to Archmages and fuck up reality, why can't demons ascent do Gods. :P

If you're talking cWoD Demon the Fallen the answer is no. The game is rigged from the very beginning including the original Fall: God created the universe, God set the rules, and God both imminent and omniscient knew the potential results and the actual outcomes. From Cain and the first murder being followed by a thousands of years long opportunity for redemption, to the broken Underworld and Charon's quest to learn mortality, and the rise, collapse, and reconfiguration of the Triat, all of it is part of the plan and Demons have little to no practical control over any of it.

On the other hand if you're talking nWoD the answer is yes and no because the question itself is flawed. In the first one assumes the Elohim and Yahweh exist, but there's no mechanical proof of their existence. Even Mages entering the collective consciousness or the upper worlds as Archmasters only find direct mortal cognates and conceptual representations of the creator. If there were a creator, in the Judaeo-Christian sense or not, its either already dead - claimed by the Exarchs when they conquered Atlantis and destroyed the ladder - or never existed as we understand it.

What gods do exist in practical form which are called gods are spiritual gods, some of which embody sins, and could be called demons. While those infernal entities do aspire to godhood, the godhead they can attain is no threat to the natural order and they don't describe any celestial origination to the universe. Even if they talk about the realm of imprisonment known as The Inferno, they don't tend to share the true unimpeachable secret of reality because a simple self-serving lie will do.

The other demonic entity comes from Demon: The Descent, and those demons don't technically aspire to the godhead. Some particularly vile demons might enjoy the worship of people around them for the "miracles" they can enact, but their abilities really are more about hiding from the God Machine and it's angelic servitors. The vast majority on their quest to find Hell and so be free from the machine would find the idea of becoming a God Machine anathema to their basic aspiration. Even so a demon who tried would be revealed and likely destroyed by the God Machine which itself isn't even a God but a sufficiently advanced intelligence we can't understand. The God Machine rose if not from humanity, well after the creation of the universe.