1. How would Toa of Stone perform a nova blast?
2. If Toa of Water can control water vapor, then why can't they control ice?
3. What can a Toa of Magetism do that a Toa of Iron can't?
1. I'm not completely sure, but I think it would be something like a colossal avalanche of stone, except exploding outward.
2. I guess because ice is for Toa of Ice to control. But Toa of Water controlling water vapor doesn't make much sense to me. Are you sure they can control it, and not just absorb it?
3. Well, Toa of Magnetism control magnetism, Toa of Iron control metal. As Anti Nui said, Toa of Magnetism can fly by maintaining a repelling magnetic field below them, like a Mag-Lev train. While their control over metal is less direct than a Toa of Iron's, Toa of Magnetism can also use their element to manipulate non-metallic magnetic things, for example plasma and the magnetized water in the Metru Nui chutes.