Tidus may not be going with Purple, but for those who are, people to act as liaisons/keep track of people, to listen out on the comms, and carry extra supplies will be good for volunteers! And then also for supply gathering, when it turns out that the islands might be good for that?

There's a roles checklist here, but anyone can take up any role! Also finding a good place for a camp.

People who can fly around (even if slowly) may be good for getting details: surveying the land, etc. Especially as they will be able to see where the heck people are heading to on the North Island.