Worren's only real other magic is summoning his weapons. As opposed to Trent, who manipulates his staves to be small, and wearable on a necklace, or Derik whose body is made up of chains. 

He can't, for instance, use the gestures to generate electricity with hand seals. They are just his chosen method of employing fire. 

You are right, I would. The tournament is designed to give people a simple ay of manipulating things, such as Worren with Fire and heat, they can be closely related, same with Earth and Metal. 

The real motivation behind Worren and his ilk. Is that they all manipulate a element, a closely related side element, and can manipulate their chosen weapons. 

Element characters can be unique, however. As an example, me and you would use the same element/side in different fashions. Worren wouldn't create magma, or use heat to propel himself. Lots of people use fire and such in different ways. I have a combustion character who employs explosions to speed himself up. 

As for your question, I would personally lean volcano for fire, air for tornado(you aren't using the tornado to break off into icicles), and steam, I would probably lean towards air, but that's just me as well. My air character, whose name I forget but uses nunchaku, manipulates Air/Ash, so I would consider steam not being too far fetched. Probably couldn't create it,b it could control it. Others may have a completely different view of it. In a tournament of this ilk, but perhaps not configured for newcomers, those things can be expanded to fit in other elements, actually, in this one if done properly, I would probably allow it not  good argument was made. 

It made sense.