All of them I'd wager. The very young ones I looked into appeared to have had meningitis.

FakeNews reported one with strange quotation marks around the parents statement that the child was "healthy" before the getting sick. That one in particular is reported to have died of brain swelling which could easily have been bacterial meningitis (strep etc..) or viral meningitis (Influenza, mumps, chickenpox, herpes etc but not human coronavirus).