Yeah, and you’d be facing issues from more directions that just Square Enix. In the lore of Forgotten Realms, the universe in which D&D and a large number of novel series are based, Bahamut is the Diety of Justice and worshiped by all Metallic dragon kind.
I get what you’re saying though (I think). You just want to the concept of Bahamut to be used as inspiration for a dragon. I hesitate at this idea because of what doing justice to the idea of Bahamut would entail. Bahamut’s powers are supposed to be supreme; so powerful relative to other dragons as to make him…well…their diety. I suppose we have had some equivalent’s though: Surt and Abraxxas, to name two, were both supposed to be “apocalyptic-level” dragons.