Worth bearing in mind that "Theion", "Cytherea", and the narrative of Creation's creation all belong somewhere near the very end of 2e. Around the same time as Sol was becoming Golden Jesus Superman, in fact. Back in 1e, he was just The Primordial King, who in his surrender became Malfeas. Nothing more was known or needed.
A subordinate spirit's overthrow of his divine king and all-ruling god is hardly unique to Lucifer, who's notable mainly for failing – most obviously, Zeus kicked off his reign in much the same way, while Marduk took down the Annunaki – but Sol's associations with the Sun, the setting's early associations with the World of Darkness, and a desire to use a less common but still recognizable comparison point which would illustrate the setting's moral leanings meant that Lucifer was a more appropriate pick than either. I don't recall when he was first referred to as "The Morning Star" – I suspect the Ink Monkeys articles, again from late 2e, because subtlety is for other people – but by that point the meme was clearly solidified.
Plus, as noted, Lucifer is usually considered more metal than Zeus.
Well, this much is certainly true. I'm not sure where "edgy" comes into it, but the God of the Old Testament is a capricious and cruel cosmic horror, by modern standards, and Exalted isn't usually shy about calling classical and ancient entities out on their era-appropriate evil. YHWH doesn't get a pass for his bullshit any more than Achilles does.