My choices:

Lisa Sparxxx: Her blubber guarantees a strong chance of surviving both famines and ice ages. Like the Taun-Taun in the beginning of The Empire Strikes Back, she can be sliced open and used as an ad hoc shelter if needed.

Steve Buscemi: He isn't one of the other choices. Plus seeing his skinny small ass try and mount a whale like Lisa creates a funny mental image. He might get crushed under one of her chins.