My interpretation agrees with this; presuming the existence of an Isabel Wondertainment, she's unlikely to have made these particular Little Misters at least. I'd assumed a board of directors myself; a predecessor Wondertainment would work too.
I find it interesting how Ms. Sweetie thinks the one person behind the Wondertainment name has to have a penis
I intended her to be totally wrong there, because everything she's experienced says she has more than one creator, and it would be silly to imagine just one person was responsible for creating her. Likely most of them were dudes, but they weren't thinking of her as a person (even though she IS a person) any more than they think of the other Misters as a person (even though they all — or almost all — are people).
It's very likely some of those did try to make her stupider for sexist reasons; but some of the people involved with that likely had other motives, like trying to make her personality more appropriate, or just trying to make her less dangerous considering her superpower (is scary as fuck). Ultimately, this is supposed to be left up in the air.
But, I mean, just look at Mr. Clumsy. There's absolutely no chance he started out that accident-prone, even when you account for the supernatural add-ons to force accidents to happen when he won't cause them on his own. Mr. Mad gets waaaaay too angry too often to have begun that way; he has also been mentally altered. Mr. Mission has had a total personality overhaul. There's been some pretty hefty work done on these people. Pretty hefty indeed.