Hahaha Elisaveta. The EBD hallmark! Please expand on the Phils, though: the triplet Marys at least make some kind of sense, but I'm struggling to apply the same logic to a quintette of Phils.
Do you know when it was published? I know the CS has (I guess inevitably, given the location) a prominent Catholic aspect from the very beginning, but some people seem to switch from Protestant to Catholic early on, presumably in line with EBD's own conversion (Nell Wilson, and in a way, Jack Maynard, since Mollie never is - I think there's another member of staff too but can't place who - may be Con Stewart), so I wonder if some of her writing predates her having any interest at all in Catholicism. Actually, please also expand upon the inappropriate rector, because that sounds funny.
mornington I'm always quite struck by how Miss Annersley suddenly rises from complete invisibility to Senior Mistress at that point. And while Mlle does a nice bit of motherliness, she's also sidelined from much of the action (as she continues to be in subsequent books) and goes all spineless jellyfish when Eustacia's missing and gets sedated and put to bed while everyone else sorts it out. Hilda seems the better leader here, already - though I think almost everyone comes out of Eustacia looking at best a bit neglectful, really, which I'm sure can't be the intended reading of it!
It's also difficult that Madge never really stops being 'Madame', in practice as well as as a figurehead. She seems to continue to be the 'real' head whenever she's present, and I often have to read back to check which of the two it is that some trouble-maker has been referred to, or is making some kind of school decision. It rather limits the scope for Mlle to be much of a headmistress.
Even ages later, there's that occasion in one of the Swiss books where Peter Chester has leaned on Madge to get a too-old new girl (maybe Naomi Elton?) admitted...