It's implied that Sarah lets her boyfriend spend the night; her mother even says she has 'The pleasures of marriage without the responsibilities'. It's obvious they're sleeping together, since she gets pregnant. Other than the implications, nothing sexual occurs.

None

None

None, the only mention is when Sarah asks if her sister has any "Christmas spirits".

No frightening scenes, there is a scene where Sarah is yelling at her mother which could be a bit intense.