BCoB and Allagan speculation?

[NintenPyjak64]

Lore or Dungeon subforum? Dunno where this falls to exactly
Trekking through 1-5 it's apparent that most if not all of the architecture in BCoB is Allagan (most apparent in T2-4)

Looking forward I recalled the screenshots of 6-9 and while the architecture is still Allagan, it's a different design, so that got me thinking, could the Allagan have various races and cultures under it? Like how we have Hyur, Lalafell, Roegadyn, etc., could they have races of similar style if not the same races? Pretty sure our current 5 races wouldn't be living in the same style of housing/building if living on their own separate from each other (e.g. Greek architecture is completely different from Egyptian since we're talking History)

Another thing I thought about is how T5 is basically Bahamut's Right hand, so could T9 be his left hand? or if not another appendage that would function as a battlefield? (Tail maybe? Shoulder? a spine on his Vertebrae?). If we are fighting on his left hand, could the third leg of Coil be Bahamut's head/heart and the final battle of BCoB?