Someone said in previous chapters that the reason the faces feel weird to look at is because the eyes and mouths are too big.
I put it to the test, and I think whoever said that was right on the money.
I tried resizing the eyes and mouth and that made the faces look much more natural without changing the art style.

For the kids, I decided to keep the eyes untouched because larger eyes reflect the younger age better, but I resized the mouths and changed their elevations, making it higher for Anette due to her expression trying to retain her composure as the maid while keeping her posture straight, and lowered Rosalena's because she's clearly not trying to hide her surprise.

I think this solves the uncanniness that I was feeling from this manga!
Thank you, whoever pointed it out!