I've only watched the anime, so is this explained in the manga? Where the hell are these little girl's parents? We know Agott comes from the Arklaum house, Richet seems to have an older sibling before she was left alone and poor Coco petrified her mom accidentally. There's no background for Tetia and we have no idea where these three little girl's parents are, other than Coco's.
We also know that before she joined Qifrey, Richet had another master and she's like 12. Do all young witches leave their house when they're like, 10, to join different ateliers to become witches? How long do they stay with their families before they have to join an atelier they know nothing about and leave their children's fates in a stranger's hands? It'd be different if at the end of the lessons the witches left the atelier to go back home, then go back to the atelier on the next day, like a school, but no, they literally live in the same house as their master.
EDIT: Also, wanted to add, in the fanfics I've read, Quifrey keeps using endearments like "my dear" or "sweetheart" when talking with his students. Does he use more nicknames with them in the English dub? I only watched the anime in the Japanese dub.