Sorry about the delay! The patch has been hectic (to put it lightly), and we've already been handed stuff for 1.19a and beyond (beyond...beyond...beyond...). /echo off

What I can tell you, though, is that a lot of exciting stuff on its way. Company quests start to reveal a lot about what is going on in the shadows and the Ifrit battle is quite epic. Ah, but I've gotten off track.

First off (alright, "second off") let me say that the lore-masters, myself included, are truly flattered by the interest you and many other users here in the forums have shown regarding the in-game lore. We understand that the LOC forum is probably not the best place to be releasing this info, as it can often be difficult to find, especially for those users who don't know to look here, as well as DE, FR, and JP users who might not be able to understand the posts even if they do manage to make their way here. Plans to expand the the Lodestone to include more lore-related articles are already underway, and your suggestions regarding in-game lore libraries have been relayed to the team. Until those plans come to fruition, however, you'll have to bear with me

Now, about those three creatures.

First let me start by clearing up the genus issue. The theory you threw out there, while a remarkably good one, landed a few yalms off target. The facts are a little less colorful, but far from boring (at least in my opinion).

The short answer: Fireflies are vilekin; wisps and plasmoids are voidsent.

The skinny: The three are in no way related, nor are they the same creature in different stages of development. It is mere coincidence that fireflies and wisps share the same elemental aspect, much in the same way that it is coincidence that some wavekin salamanders and scalekin drakes are both aspected to lightning.

Ah, but you are probably thinking that this does not explain why all three creatures use the same attack (Stellar Flame). It is widely known that special attacks are usually only used by members of the same genus. For example, though they are both of the same class (cloudkin), only apkallus use Yawn, while only hippogryphs use Shriek. Following this line of thinking, wisps and plasmoids should not be using the same techniques as fireflies. So what gives? Well, it has been noted that wisps (widely believed to be the spiritual remnants of long-deceased souls) and plasmoids (in some circles, thought to be unstable manifestations of lightning-aspected aether, in others, to be a by-product of Garlean magitek technologies, though most likely a combination of both) display only limited cognitive abilities, and react to their surroundings driven more by primitive inherent tendencies than complex reasoning. Using these observations as a foundation for their theory, certain scholars have formed the hypothesis that when wisps and plasmoids cross over into Eorzea from the void, they mistake the glowing fireflies of this world as brethren and instinctively begin emulating their actions, thus the similarities that we see between the species.

Now to answer your second question:

Coblyns and doblyns both fall under the kingdom (regnum) bloodborn, the class soulkin, and the genus coblyn, but are of a different species. I suppose you could liken them to lions and leopards on Earth. Both are of the same kingdom (Animalia), class (Mammalia), and genus (Panthera), but from there the branch splits.

Another example of this would be gigantoads and vodyanoi. Both fall under the kingdom of bloodborn, the class wavekin, and the genus gigantoad; however, as with the coblyns/doblyns, the two are of a slightly different species.

I'm going to leave questions of cross-breeding unanswered here, because that's a whole other can of worms.

Just as a side note, it is common for many creatures in Eorzea to have the same genus and species name (as seen in the aforementioned coblyns and gigantoads). Early naturalists such as Frandelont Raimdelle (author of the Raimdelle Codex) are to blame for this.

I hope that helps! Now it's back to the Pits for me.