loved the pictures. Too bad the answers disapeared as soon as they were filled in. (maybe for extra difficulty? On the easier planets/moons that is fine, even yellow boxing. But the last say 10-15 are tough and it gets hard to remember what you had allready tried)
Wow! Didn't know Hydra and Nix even existed! Maybe change Pluto from Planet 9 to Dwarf Planet 1, then it would be up to date. If it was up to date, I'd nominate it for being a featured quiz!
https://en.wikipedia.org/wiki/Ceres_(dwarf_planet)