But the battle modes for the Toa come from combining their weapons with those of the protectors. There are no secondary sets for the skull wave.

But the battle modes for the Toa come from combining their weapons with those of the protectors. There are no secondary sets for the skull wave.

No, what you're referring to are the "powered up" modes. The Battle Modes are the Toa's default modes (except in the case of Gali, who is built in Adrenalin Mode and can be switched to Battle Mode).

Anyway, I seriously doubt the Skull Villains have any alternate modes along those lines. There are no obvious alternate uses for their weapons, nor is there any indication that they have any alternate configurations (apart from Skull Warrior, who can switch between a bow and a spear as his weapon of choice).

... I thought the new BIONICLE was supposed to reduce confusing terms.   So what's the difference between battle and adrenalin modes?

Adrenalin Mode is usually geared for higher mobility--thus stuff like the flippers, or the stormarangs on the feet, or the wings, the skis, etc. Whereas Battle Mode is just weapons.