Two things I, as a newcomer, just noticed

[Hinoto-no-Ryuji]

The Sharlayan of the Dravanian Hinterlands - which is actually a colony of Sharlayan proper, a nation further north and separate from Eorzea/Aldenard - was abandoned some 20-odd years back, when Garlemald made its play on the continent. Likely, the Aetherytes just fell into disrepair as a result of this. Their shape is probably meant to hearken back to their pre-Calamity origins; while the 2.0+ Aetheryte design may have lore behind it, I really don't think there's anything more to the design of the ones in the Hinterlands than that.

As for the dragons: we don't know what, exactly, Middy means by that. It certainly could mean he's from a different planet - dragon biology is definitely very alien - but nothing has been definitively stated one way or the other. Pretty much anything about their origins is speculation at this point.