It's possible that for elementals in 3e, while Garda Birds are a specific type of elemental, Garda-bird-ness in general is a sort archetypal state that other fire elementals can aspire to or approach asymptotically.
I didn't conceive of Teo as any sort of elemental in specific. (Actually, I didn't conceive of Teo as Teo until like the last day of writing. I'm terrible with names, so Teo and Suma got named frantically at the end of the process -- up until then they were just "The river god" and "The firebird".) You could certainly have 'em turn out to be a young Garda Bird, though!