I'm not exactly sure what the magic school bus is, but I'm very sure Rive should not supervise children! Even though she probably did and the school bus isn't magic, but is just a tardis with a working chameleon circuit!
This is almost like an actual Doctor Who episode. SO The Doctor's daughter played the Doctor's daughters in 'The Doctor's daughter' was friends with the Doctor's daughter then married the doctor and had the doctor's daughter
Mama Toph playing the Papa role. Who knows, maybe she had to be both for little Lin. I wish they would release a full series after Korra showing what happened between The Last Airbender and The Legend of Korra.