So, here're my thoughts on the "Sampo is an Emanator" theory:
I think he is.
To explain my reasoning, I'm going to first say that it's for the same reason I do not think Sparkle is an Emanator. Aha is repeatedly stated to be chaotic and will destructive things on a whim to amuse itself. This is very similar to how Sparkle herself operates- doing whatever she wants regardless of morality.
We know that Aha has a habit of blessing things that just don't make sense for it to bless at all, like the Mourning Actors and the worm. So making Sparkle an Emanator doesn't really follow that pattern given the similarity in ideology.
However, Sparkle also openly complains about Sampo having self-imposed limits, and Sampo himself also states he can't stand for Sparkle's idea of Elation.
We don't know too much about Sampo's views on Elation, but he seems to prefer laughing with people to laughing at people, or keeping everyone else in on the joke. Him abiding by morals and rules would then contrast Aha's more self-centeredness and inclination towards chaos. But, he still does not reject Elation like the Mourning Actors do, and instead follows it as a Fool.
So, why make Sampo an Emanator? Because it would probably be more entertaining for Aha to see a guy with a contradictory ideology still following Elation than someone who does the same thing as the Aeon.
Not much of a theory from this yet, but I noticed when playing Hanu's Prison Break, every single loading screen to enter the bubbles was Sampo's. I was like er, could this be a coincidence? But I checked on different accounts, and watched a few YouTube videos, and all of them also had Sampo as their loading screen. It makes me think it's either an error or something the devs intentionally did, as loading screens can be specific for quests to build up hype or drop hints. Maybe Sampo was the supplier for this dream? Tell me what you think abt this in the comments or tags <33