What is the ruling on one who tries to make a person praying laugh, and on one who says, "I will invite the Angel of Death for tea," and are these considered acts of disbelief (kufr)?

Trying to make a praying person laugh during their prayer is a sin and an act of disobedience. As for the statement, "Shall I offer you something to eat or drink before the Angel of Death arrives?", it indicates a lack of concern for the moment of death and may suggest disrespect towards the angels, even though angels, by consensus, do not eat or drink. However, the one who utters this statement does not commit an act of disbelief unless they intend to mock the angels.