I think Tahnok Kal is plasma because it carved the word"kal" and the toa nuva on the cave's wall in comic 9 with something burning, and burning plasma is often a weapon in sci-fi and space games. I think Gahlok Kal is electricity because it is a major element of a thunderstorm.(Then agian, for the same reason it could be Lehvak Kal.) I don't know why, but I think Pahrak Kal is sound, but the use of the power is anyone's guess. I think Lehvak Kal is vacuum because a vacuum has to do with air. I think Nuhvok Kal is magnetism because it is the only thing left.
What do you think? Huh?