As I understand it, there are elements and then there are associated energies that go with them.

Earth -> Acid
Air -> Electric
Water -> Cold
Fire -> Fire (yeah, I know)

The addition of Sonic, I believe, is like Fire where it's both the Element and the Energy type.

Thats how I laid out the Movements and Defenses. Elements in one and Energies in the other.

I agree that Positive and Negative are really Divine territory and as such unfitting.