And after all that wreckage of an essay... sorry for my frankness, I believe you missed the point.
It's true that the mythical form of each pathway was different,
It's true that the form is changeable by the authority of the pathway owner (Seq-0 and above)
For an Angel-rank, the most they could do was modifying the knowledge carried within their pathway, and exert some degree of dominance towards the lower sequences, but not about the mythical form -or so I believe.
However, so far, we know that the direct descendant of those Ancient Gods -ones who born a mythical creature "could" polymorph into humanoid form when reaching sequence 1 (likely)
-the prime example for this case were Antigonus, Amanises, Herabergen,
While those who could polymorph into human form at seq-2 currently known so far, was mr.Azik (he was born as winged serpent)
What is currently unknown was the truth about the creation myth:
Whether those Ancient Gods were truly born directly from Original Creator's partial aggregation of scattered beyonder characteristics that came to life (thus, born more than just a mythical creature, and removing the need of apotheosis ritual), or those stories was another fabrication of history.
And yet, the question still remains:
Even if Omebella was not a first generation giants, her being a cyclops means that she was born with a minimum of 1 twilight giant beyonder characteristic.
Similar to how a sanguine was "naturally" born as a seq-7 Vampire of Moon pathway.
Another case was Groselle. He was born when the rational giants began to appear in the giant community (meaning, later than Omebella), but he still retained his ancestors characteristic: being a cyclops, one-eyed giant and of Twilight Giant pathway
In simple terms: The child of a Twilight Giant Cyclops must be a "giant"-blood of warrior pathway, too.
This method of heredity-inheritance for beyonder creatures, means that without the influence of beyonder characteristic affecting stabilization of genes over the generations, an individual would be born as normal creature, but carrryng over the fenotype change caused by multiple and prolonged succession of beyonder characteristic
I.e:
Established generational beyonder creature/family/race -> "Normal" descendant
Sanguines/Moon pathway -> Human with red eyes
Elves/Tyrant pathway -> Human with bluish hair
Cyclops/T.Giant pathway -> Half-giant human, XXXL-sized human
Hunter pathway-> Human with reddish hair
Demoness pathway -> Human with stunning visuals
Devil pathway -> Human with ice-cold blue eyes (?)
Death pathway -> Human with darker yet pale skin (?)
Now, with the new information (just a guesswork of Lumian's),
Zedus and Omebella were twins,
yet having different but adjacent pathway.
Zedus was of Moon pathway, and his appearance was similar to those of Sanguine: a beauty (man) with red eyes
Now, Omebella... was of Mother pathway: A Cyclops/Twilight giant in appearance... too farfetched to be called twins with someone from Moon pathway.
Who was the biological mother of Omebella (and Zedus)?
Were their beyonder power came from boon? (in which, in this case, could explain why their body had manifested no beyonder characteristic after their demise)
Her son with Aurmir were also a cyclops of Twilight Giant pathway too.
Last time, I mentioned Kotar as comparison, now I will compare her with Herabergen.
Herabergen's species was noted as Dragon; meaning he was born of visionary pathway (or so I think),
but switched pathway to White Tower for seq-2, OR,
consumed more Seq-2 White Tower characteristic later as he was called the dragon of wisdom, (mixed pathway, as Wisdom was far from the theme of dream, imagination, but still relatively close to mind aspect)
This way, his species as dragon but having White tower characteristic seems to be still under the realm of being plausible.
Then he "polymorphed" to human form as Angel of Wisdom when he came under ASG. and he never manifested as dragons again [SPECULATION]
It's normal for the first generation of the races at the time to have mixed pathways, of non-neighboring pathway even, however their physical appearance would still follow their dominant pathways [THIS IS MY MAIN FOCUS; keyword: first-gen, dominant pathway]
On the different account, being Kotar and Antigonus
They had similar case with Omebella in regard to their species and non-neighboring pathway -born as wolves-kin (darkness pathway racial trait) however carrying not darkness beyonder power but Fool pathway;
however theirs were easily solved by logic as their origin was Flegrea who carried both characteristics of Darkness and Fool, with Darkness pathway as the dominant one shaping his racial trait as wolfish.
So, Omebella being one of the earlier generation of giants, but having non-adjacent pathway to twilight giants as the dominant ones, yet having the appearance of one-eyed cyclops as the twins of a sanguine-like person, seem rather illogical.
Unless she had parents with mixed traits like Flegrea or Gregrace then many reasoning would fail.