I do not know where you see a relation of any kind between Halloween and Christianity... Halloween is a party for witches, which have been burned big time in our countries by kings and bishops. Xmas is a worldwide celebration, not even mentioning St Patrick's day, which is Irish people's day. They may have a christian origin but they are big party time for most people in the world. A cross to me is a sign made with 2 perpendicular lines. And a crescent is a delicious french pastry. I do not see anything more in them than that.