Pilot of the plane:
It wasn't your fault, you didn't know what would happen.

Stepped up leader:
Keep an eye on your fellow passengers and minimize casualties.

Medic:
Finally that training pays off.

Survivalist:
Whatever happens, you're going to survive it.

Moral support:
Just a chill guy.

Passenger:
The basic passenger, try to stay alive.

Each of these roles has its special perks and condition. They can and probably will alter how the story goes as they are pretty important, manage these well and you will survive the frozen artic.