Is it permissible to bury a Christian child in a Muslim cemetery, and what is the expiation for that?

A Christian child may not be buried in a Muslim cemetery, following the ruling concerning their parents. If a disbeliever is buried there, whether a child or an adult, the correct approach is not to exhume their grave, unless they were buried in the sacred precinct of Mecca, in which case they should be exhumed as long as their flesh has not decomposed. There is no specific expiation for burying a disbeliever in a Muslim cemetery; rather, what is required is repentance.