The kids thus far represent America, Britain, China, Japan, India, Ghana (for rather sentimental reasons), Brazil, Russia, and Nigeria. Who should be added to the list and who should be voted off? If you're advocating a country I don't know much about, is there a likely character trait I should look out for? Keep in mind that it's present day, the age range is between fourteen and eighteen years old, and that these kids have been hand-selected by very smart aliens to serve as diplomats. In other words, no blatant morons here, although residual prejudices could slip under the radar. Earth will remain ignorant of this visit for a few years, so no politician's kids, either.
For extra credit: A character from one of those small, oft-forgotten countries hardly anyone knows about is included in the group, for no real reason other than a clerical error. Where should she/he be from? Think places like Tuvalu or Moldova.