As I understand it, Jewish ethnicity follows the maternal line, so in that case their father’s last name could potentially be anything.
Bennett is from an American family. Jews did not traditionally have family surnames, but adopted them recently in response to government demand in Western Civ. Many American names are like this.
Bennett, said to be a variation of Latin Benedict, which means blessing, for which the Hebrew translation is Baruch or variants. Baruch is a popular Hebrew name easy to Latinize.