The Egi Conundrum: Heavensward and Beyond!

[Exodus-E]

But since Garuda is already a wind aspected Primal I feel it would be more likely for Bismarck to be a different aspect. Unless of course it's possible to have more then one Primal/Egi of the same aspect.

I think it's very possible.
After all, we have Ifrit and Belias, as well as

Phoenix, as shown in T12

for Fire-aspected Primals thus far, so...