Ratsack or bear box?
Quick answer: Ratsack
Reason: No bears in Havasupai, so you just need something that is rodent-proof
The Havasupai website lists bear box as the thing to use, but they do not require it. The only requirement is that you keep your food safe from wildlife. Ratsacks are much lighter and fold down much smaller than bear boxes. Therefore, ratsack is our answer to this above question.
Best practices for using a ratsack:
1) Place all your smelly items (food, toothpaste, etc) in an odor-proof opaque (non-see-through) ziplock bag.
2) Place that in the ratsack and suspend it for a tree limb.
How much water do you plan to boil at each meal? The biggest difference between JetBoil and other backpacking stove+pot combos is the volume of the pot.
Backpacking meals on average take ~8oz of water per serving. If you're going solo, the 0.5L JetBoil is usually sufficient - that will boil about 16oz of water in one go so you have enough for a meal and a cup of tea.
If you're 2 people, a backpacking stove plus ~1L pot will allow you to boil enough water for 2 servings plus 2 cups of tea/coffee in one go. Or you could take the JetBoil and boil water in two goes.