Ryik's suggestions make me think of a pkmn mystery dungeon type of story, but with regular trainers which might be fun. I think combo of sandbox and episodic goals is a good idea. Perhaps have one larger long term goal (assuming the eventual group has been together for a least a little bit, maybe their long term goal is either to find a new place to settle after being ousted from their previous one or something more ambitious as mentioned. Finding a place untouched by the calamities, or restoring the world with the help of Rayquaza, etc.), an episodic goal as needed, and then of course each character can carry their own narrative too that can contribute or be separate from the group goals.

I have a fever so I hope that all made sense lol.

Personally I was planning to play someone whose goal is to find a goal. A rough and listless sort who would slowly bond with other characters and become interested in their plans while she searches for her own way. With a Morgrem as her partner :cool