I agree with someone's comment on Gelbooru that those squishy artstyle ruin the beauty Hana and Noa may have had otherwise. It ruins the moe potential, and I can't stand it too.
Koyori, however, for some reason, is pretty moe the way she is.
Yuri Kuma Arashi and Lapis https://up.heyuri.net/src/4314.png (also recent Magic Maker https://up.heyuri.net/src/4313.png) are examples of sweet and sexy artstyle.

Speaking character-wise, cool and polite loli type is sexy. She's so short with you and maintain a distance, how will you win her dere or childish side?
https://gelbooru.com/index.php?page=post&s=view&id=5967084