Most of my friends were at ISB in Brussels. I went my last year to St Johns in Brussels...since it was a half a block from the house in the American Ghetto.
Sr class...16 kids from 7 countries. Much the same as your experience. Parents jobs were mostly business and EEC related. Had some consular reps and very few military. Most of the military were located and schooled at SHAPE.
The military friends I made were from hanging out in bars or at the U of Maryland classes I attended that were on base. First 15 hours of college were taken there.