Holland Christian is one of several western Michigan nonpublic schools that have helped shape Ms. DeVos’s views of elementary and secondary education, and that her critics fear she will draw from to upend the nation’s public schools. The private Christian school that she attended, another that she sent her children to and a hardscrabble private religious school that she has long supported have dominated her time, money and attention. Public neighborhood schools — the vast majority of schools in this country — were hardly present in the billionaire’s childhood or adult life.