Hm, I think secretary's description fits both INTP and ISTJ (although the logic thing sounding more Ti) but what convinced me a bit more was how she was a very diligent child and was constantly studying, doing the same thing over again. Not to say that INTPs can't be good at their studies, as I've met many who were, but her tendency to somewhat mindlessly follow the same schedule feels a bit more extreme Si rather than Ne. Her obsession with prez may also help at figuring out her type but I'm not really sure as to what it hints at,,,
I agree on Yumemi,, her personality is pretty difficult for me to pinpoint from the 4 types I narrowed down to, but your explanation makes sense ^^
I think Kirari's comparison with Yumeko threw me off, but I was also under the impression that her academy playground scheme was just a thing she did for the 'fun' /Se,, and that her strict viewpoint was a result of her logical Ti. However, now that you mention it, her relationship with the rest of the counsel seems pretty Te and her entj Se could be going out to play,, which also makes sense

I know this isn't the most accurate way to tell, but she also seems to keep to herself a lot (introversion),, but either way I can see both types
My first impression for Mary was also ESTJ, but for now I'll just see her as a passionate INTJ haha, perhaps we'll have a bit more to work with after the manga's upcoming arc?
--edit bc I just read chap 43-- *very light spoiler*
I have trouble seeing Mary as an ISTP bc of her lack of reliance on Se, shown when she leans down to Yumeko to tell her she'll be prez (referencing her v beginning goal) despite her shortcoming of not being a gambling addict/being unable to take such in-the-moment risks. Also when she realizes that Yumeko said it'd be fun with her, she's able to quickly connect the dots of her personality and the shuffle she saw earlier (Ni) (it was pretty obvious, but I'm just going to assume that it was also very immediate)