Semantics. All living beings in the universe of XIV are aether. The ARR quest "What little Gods are made of" already explains the cycle of death and rebirth as aether given new shape once a being has passed on. You also don't know if auracite can't be teleported and even if it can't the aether itself could still be drawn into multiple vessels at any given time, because as I mentioned before, Urianger created one in such short notice only after we failed to properly contain the light, as a way of dealing with Emet. You also don't know it couldn't contain the aether even though that is the purpose of the auracite to begin with. Killing an Ascian's body and draining their aether into it.
Again, if it could briefly contain a fully joined Ascian (14/14) as it was supposed to with Emet, then i'm all but certain it could contain a single warden for much longer. As we did (9/14) with five, however briefly it was that we did.
I know some of the wardens are named after words for Love. I'm saying all the others kept something of the form that was taken over. I just feel pity for who or what it was before. An elemental maybe as others appear as Sin Eaters in the area (Forgiven Bribery and Forgiven Vainglory). Which begs the question if you believe elementals are able to be wardens since they are pure aetherial spirits and don't really have a body as they are just beings that form themselves when they wish. If it was an elemental, was it possible for it to become a warden without a vessel to fill? Theoretically, some of the Fae are just spirits of the deceased as well.