The mini trend is branching out to younger families too. Some are buying handsome suburban homes in top school districts — outposts where mothers and grandmothers live with school-age kids so the children can attend middle or high schools to be better prepared for American universities. Fathers generally stay in China to earn the needed income. The trend has the potential to expand the talent pipeline into Chicago. But the city still lags far behind Los Angeles; San Francisco; Vancouver, B.C.; and New York, observers say, witnessing a much smaller, more buttoned-down version of the buying binge by Chinese parents in those coastal markets.