It has been divine practice that any nabi (prophet) has not been placed under obligation of any non-Muslim. According to the research scholars of Islam all ancestors of Holy Prophet Hzarat Muhammad (peace of Allah be upon him and his progeny) were momin and muwahid (believes and Muslim) as the writer of "Seerat-nabawiyya" while quoting the saying of Imam Fakhr-ud-din Raazi page 41 of his book writes that Holy prophet has said I had continuously been carried /transported from the aslaab(the loins) of Tahereen (pure chaste men) to the arhaam (the wombs) of Taheraat (pure, chaste women) and Allah had said that polytheists are Unclean and impure. So it is wajib and necessary that there should not be any of holy prophet's ancestor (grandfathers of grandmothers) polytheist.
