Only one child death occurs on screen though there are references to others. There are a few very brief flashes of the body. Multiple children attempt to hang themselves while under Marianne's influence but they survive due to adult intervention.
Addendum to a previous comment: It isn't a quick spit, they drip a lot of spit onto the corpse. A possessed person also spits on one of their friends during a seance.
Multiple claustrophobic scenes including one inside a refrigerator and one in an open grave. A character appears within a small hole in the ground throughout the series.