The tiniest one is super cute!
Definitely agree about the cel shading too (looks really good on the 64x64 version).
I really enjoy the palette used here and the charming stylisation of proportions in the 64x64 piece, with a pleasant hard-cel shaded look that minimises AA and also keeps background elements distinct from foreground. It's also real interesting to see the further pushing of proportions in the smaller pieces, where the eyes. front hair bangs and ears keep as similar a distance and size as possible. It's definitely not something I would have thought when shrinking sprites down to size.
Thanks for the thorough feedback, StevenM!
Also, Thanks, IIII !