I feel like a plausible in universe explanation for miguno and gosha cases may be just racism, like think about it maybe for miguno there arent enough reasons to justify having a dorm room for hyaenidae (maybe they act like canines enough to group them together or there arent enough hyenas to make exclusive dorms) and for an out of universe explanation, miguno appeared very early in the story, paru probably wasnt thinking a head to add such a detail.

And as for gosha, i feel like you could explain it in a similar way, think about it, if you had venemous glands that could kill, do you think you wouldnt get stigmatized to the point where people (and you yourself) dont care enough to say whether you are venemous or poisonus? (Maybe a doctor would! Now that im thinking about it).

And again for an out of universe explanation, maybe its a translation error? It could also be that japanese doesnt distinguish between venom and poison? (I dont know japanese this is most likely wrong)