Writing Style Advice?

Um, the title may be misleading. I was exactly sure how to appropriately title this...

So, basically I'm writing a cross over fanfic for Avatar: The Last Airbender. It'll take place before Aang's time. But, anyway, here's what I need advice for: there are 12 characters. Three of each element. My question is more of a vote, or I am open to suggestions, on how to go about this.

Should I:

A.) Write each chapter individually for each person.

B.) Write one chapter dealing with each element, and it would contain sections for each individual in that element. So one chapter would be Fire with Characters A, B, and C while the next chapter would be Earth with Characters D, E, and F.

C.) Story arcs centered around a theme. Like one arc might be entitled "New Roads" in which a random grouping of characters (Characters A, D, G, and H or something) embark on new journeys.

Any other ideas or any votes?