fair enough
I think it still works, though...2 August 1990 – 28 February 1991 are the dates Wikipedia gives for the Persian Gulf War. So as long as Essam and Edriss got busy pretty much within months of landing on Earth (I do not have the Visser timeline anywhere near as figured out as TAC/THBC, what with all of the narrative jackknifing), then they'd have conceived in late 1990 and their kids would be 8-9 anywhere between 1998 and 2000. Which seems...fair, at least on the earlier end, as long as the bulk of the series took place in the first half of books, as far as time goes.