Love that avatar, btw...tigon or liger?
To the questions:
We had people sign up well in advance, as late as a month to the Burn, and everyone sent in their money to one central Kitchen God. The kitchen worked well for the several years we did it, to the point where we got quite elaborate and it became the literal and geographical heart of our camp.
We had no trouble getting people to sign up for shifts, they were practically falling over each other for any position. We had everyone in the kitchen meal plan take three shifts; you could be a chef, a helper, or cleanup. One couple actually took on most of the cleanup chores, for some reason...I was trying to push for everyone who ate a meal take one pot or dish as well as their own place settings and have everyone on cleanup, but it didn't pan out.
That having been said!...
Our group is blessed with an abundance of foodies. You probably can't make a project like this happen unless everyone is as passionate about their food as they are about their art.
Another caveat: in this day and age, it's <b>VERY</b> "in" to claim a dietary exclusion of whatever sort (or even multiples concurrently), and I all but guarantee you'll have at least one person in your camp whining, "[Common ingredient here]? Oh, I can't eat that!"
Not a dig at those who actually do have diagnosed food allergies, but the truth is, food allergies are not as prevalent as everyone would have you believe. The way people carry on, you'd think those who don't have a sensitivity to some kind of ingredient are the freaks. Most of the time it's just someone's way of making a political statement in the kitchen, exercising a passive-aggressive tendency, or they have an intolerance to something — gluten, dairy, whatever. Tell them to take Lactaid or Bean-O and deal with the farts for a few days.