Allah says Prophet Nuh’s son and Prophet Lut’s wife is NOT his from his Ahl (Family):
11:46 He said: O Nuh! surely he is not of your family; surely he is the doer of other than good deeds, therefore ask not of Me that of which you have no knowledge; surely I admonish you lest you may be of the ignorant
27:57 Then We delivered him and his family except his wife; We ordained her to be of those who remained behind.
Every Prophets ‘family’ is different because in the holy Quran it is clearly the spiritual connection which connects them all, not the biological.
Sarah was ahlul bayt because she was the mother of prophets (note she was not referred to in this way in Qur’an until it was revealed she would become a mother). It was the bond of motherhood that made her ahlul bayt not marriage. Also note that Sarah was the cousin of Hazrat Ibrahim (as). More info can be found here: The Word House (Ahlul-Bayt) in Quran