I know that all Jews are Bani Israel but not all Bani Israel are Jews. Are Christians Bani Israel as well, do they descend from Prophet Israel (AS)? This is not a duplicate, the answer to this question is not in any of the other articles, I want to know if Christians are also Bani Israel, I'm not asking about the difference between Jews and Bani Israel. Just please answer this question it's not a duplicate

As a Muslim it is my understanding that Jesus was born to Mary(P.B.U.T) and the person who took care of him was Zakaria. However, I am reading a book on Jesus (written by a Christian) that claims it was Jacob who took care of Jesus. It never mentions Zakaria. I wonder how and where this relationship between Jacob and Jesus came into existence.