Lisa, there were dozens of Christian families in the IoM, and as Tom said, three wills of William Christians from different parishes who died around the same time. It is unlikely they would be all (if any) descended from William Christian b.1608.
Have you traced your family back one generation at a time from your grandparents to their parents, etc., with each generation proved through wills, parish registers (not IGI), censuses, land records, etc., until you reach William b.1608?
Who was your closest ancestor who was born in the IOM?
Sue