I think feruchemy would be my favorite because you can reuse the metal storages and stuff, and you don't have to stab people to get powers. And I think the most interesting feature of the the Metallic Arts is compounding, and I'm really curious about compounding Chromium as well.
I'd probably eat the ration bars first, so the chicken has some time to lay some eggs that I can also eat.
My favorite spren is probably cryptics, I just find them to be funny for some reason (maybe it's their lack of understanding what humans do)