Great topic; I have a 9 month old, and been thinking about it too. I was going to pack 1-2 cans of similar in my BOB, but she's a breast milk baby (though all the frozen milk is going to be trashed if power out for too long ) She can do soft stuff like purees, ok with some harder stuff (small chicken, bread, ham, yogurt). I assume your kids are the same?

Then ... go-gurts ( I think they don't need refrigeration), those fruit packet thigies that look like Capri Sun packets, maybe some pita or tortillas? They pack small, can break up easily. Obviously cereal is ok, maybe those breakfast sized little boxes that come 10 to a pack (they still make those?!?). Worst comes to worst, you chew up your food and give it to them (gross, but works for lots of birds).

Containment? Uh ... well, I think you might have to sleep in shifts and just watch them. Tethering is an option, but really, how about trying to pack some of their toys and keep them occupied? Tent is a good idea, especially if you play camping in the yard and get them used to it.