精霊 are the elemental demons: Erthys, Aeros, Flaemis, Aquans, etc. You're thinking of the 御霊 (Mitama), which are created from fusing Elements/Primes. (Boy, did I have a shock in Devil Survivor 2 when I discovered I couldn't fuse Mitamas until New Game +. ^_^;)
Anyway, I have two issues with Feybird: Atlus' species names are six letters or less, and they're a single, non-compound noun. Like I said, I'm all for changing it, but I suggest we change it to something that matches the existing naming pattern. (And yes, I know "Element" is actually seven letters; I'm fairly sure the six-letter restriction is more a matter of screen space than data space.) I'm not trying to control the project or anything; I'm just throwing in my two cents.