We know that Markless magic is a thing, if we're calling it thaumaturgy due to it being God(s) (markless) magic then I'm cool with that.
Is the Chorae itself actually material in the function of the object Mimara created? I don't know if that's actually the case - but certainly it can be easier to change the function of something than to create from scratch. Mimara and Kellhus' thaumaturgy are obviously going to be invoked in different ways. Kellhus directs things to happen through force of thought, Mimara through force of will. She thaumatically wills the chorae to function as she needs.
Achamian is confused when he sees Kellhus floating and whatever else markless magic , so him having no useful insight for what Mimar did is no surprise.
Yeah, sorry, I am terrible with involving my own personal jargon into things. Indeed, I refer to Magic of a "Divine" nature, and so Markless, as "thaumaturgy." I think both those aspects are key, as the Psûhke is Markless, but not what I would call thuamaturgy, specifically because the further factor of a Chorae not working on it.
Ultimately it's kind of unclear just what Kellhus is actually doing to get Markless sorcery. It might be thuamaturgy, as I'd call it, via Ajokli, or it might actually be something like Titirga's proto-Psûhke.
In any case, I think the end product is slightly different, because in Mimara's case, her "power" seems to be in Judgement, in "setting the frame" of the world. In Ajokli (and maybe Kellhus') case, it's about manifest power over objects in the world. But that could well just be part and parcel of the source of each of their "power." Mimara's come from the Cubit, which is the "passive" Frame of the universe. Ajokli, et al, comes from a very different place, metaphysically speaking, a place necessarily
within the Frame of the Cubit.
Anyway, in the case of Emilidis, my guess, based on nothing at all, is that he was an amoral tinkerer and likely did what he did by ruthlessly trapping and exploiting souls.