Before starting, I should point out that I uploaded pictures for the first two here.
Now to address some things.
1. The Hero Nuva are not toa. They cannot use mask powers, or become turaga. They only have received a core power and toa-strength elemental control from the energized protodermis.
2. For this, quaza prevents destruction by energized protodermis. It makes it that they can either be fused, or are transformed. (Hopefully nobody needs this note that it is non cannon.)
3. All Hero Nuva have Nuva tools, that can channel their elemental power.
4. These M.O.C.s belong to Yuedom, who also uses this account.
Now, Here is the First one. This is Stormer Nuva. The energized protodermis gave him the element of ice, along with the core power of shattering. This makes him one of the most dangerous, and possibly the most destructive of the Hero Nuva. His weapons were replaced with two Frost Blades, witch are just regular blades.
The other one is Furno Nuva. He has the element of fire, and the core power of telekinesis. His system, like Stormer's stayed pretty much the same, without any really big changes to speed or strength.