Hey imaginarywhale. I'm an admitted UChicago 2012 student and those were the 5 essays I had to choose from when I was applying so yep those are "last years" essays for you even though, confusingly enough, they say 2008-2009. The new questions came out around late July last year if I remember right.
Oh and if you're worried that you won't have enough time to get a head start on college essays early in the summer, don't.
I applied EA and only got started on my essays about a month before the deadline. You'll find that one night when you get an amazing idea your essay will seem like it's just flowing out of you and you'll be done within like an hour or two (w/o proofreading of course) Don't stress, have an amazing time doing what you're doing visiting a third world country and hopefully your experiences on the trip will turn into a great essay idea so your trip was a jump-start anyway
De nada