Are the Christians of Egypt considered People of the Book, and are their slaughtered animals lawful to eat and is marriage to them permissible, given that they do not pay the jizya?

The People of the Book are the Jews and Christians, and the ruling concerning them does not change with the difference in times or places. Their not being obligated to pay jizya does not affect their status as People of the Book, because the suspension of some rulings regarding them does not suspend other rulings, such as the permissibility of marrying their women and the lawfulness of their food and slaughtered animals.