Given the artist's seeming preoccupation with topology, maybe this just worked because an inverted manjuu is topologically identical to a regular manjuu. For that matter, discarding things like hair, wings, skree legs, or accessories, any non-bodied yukkuri is topologically identical to any other non-bodied yukkuri. Does this mean you could use topology to convert one yukkuri into another? A Reimu to a Patchouli, a shithead to platinum-badge material, an Unyu to a Flan...
Ah, but even if you're correct, we don't know if the fanon logic of each species of yukkuri having different fillings applies or not (e.g. Reimu's filling being red bean paste whereas Patchouli's being raw cream).
Same could be said for another fanon logic stating that the yukkuri's filling dictates whether if it's a so-called "shithead," or a "nicehead."
However, if by some chance the neither of the above applies to Kodoku's yukkuri, something Kodoku is yet to confirm, your hypothesis might work out yet.
If you mean type of filling dictating shitheadness or niceheadness, no, type has nothing to do outside of the species characteristics, aka what makes a marisa a marisa and an alice an alice.
What the fandom believes is that usually that sometimes shitheadness is natural and born with, sometimes happening even in a family of niceheads having a shithead kid, though the ammount of that event happening is way lower than a nicehead yukkuri being born in a shithead family.
While one could say that the filling genetics may determined those "naturally shithead or naturally nicehead", it has nothing to do with filling type, only in the "genes" or whatever the yukkuris have to transfer species memory material.
Long made short logic of "bad evil genes making bad evil people", it doesn't matter the filling type, only exceptions being rare species since many seems to just not have the shithead material at all.
Just to make things clear, it wasn't my intention to say that the type had any different effect in a yukkuri's behavior.
In my last post, I only mentioned the two completely separate concepts stating that the filling dictated a yukkuri's type, and the filling each had some genetic properties which could determine its personality.
But then again, all of these things we're talking about here is based on fandom that the artists either choose to, or not to use. We have no solid base upon which we could discuss them.
Shanghai Alice, that doesn't meant we can't put our crazy doc lab coats and put on the spiral looking glasses and mess up our hair and start talking about the SCIENCE and MAGIC in talking manjuus.