Statue of the Unsung

[Hinoto-no-Ryuji]

I'm definitely with the "4 is Bahamut, 7 is Ratatoskr" team. 7 is the only one whose horns really match that Ishgardian relief (four curved, forward-facing horns, two on each side, one above and one below). Considering that Primal!Bahamut was summoned by Tiamat and others who knew him in life, it's not unreasonable to assume that he bears more than a passing resemblance to the real thing, and 6 has an eagle-like beak that is absent in Primal!Bahamut (also, less horns).