Ruling on the call to unite all religions

What is the ruling on buying from the kuffaar when there are Muslims around?

He became Muslim and he has kaafir friends

He promised a kaafir that he would go to the church with him

Her mother told her that a fortune-teller said that her marriage will be miserable!

A person claims to know where stolen items are

A person who tells people who are present about private and secret matters

Ruling on swearing by the Prophet peace and blessings of Allaah be upon him)

People claiming that they can make lots of money by using the jinn

Is there any connection between tracking skills and marriage to the jinn?