My 3 youngest (8yo, 8yo, 9yo) love online games where they earn points to buy avatar stuff. I'd love to see a blockchain version, especially one that can get them familiar with what NFTs are and how they work.
BTW, I have two daughters also (8yo, 9yo); both are adopted (from China).
My 9yo daughter hates dolls, dresses, and the like. My 8yo daughter loves them. So, definitely include some 'rugged' styled outfits as well (maybe even allow them to become worn with use).
Also, my 9yo is extremely competitive; so multiple competitive angles would be a plus, too.
Thanks for sharing; looking forward to seeing what you come up with.