Regarding your questions, no, the descendants from Advaita are to be considered as dvijabandhu, that is, unless they are like brahmanas, that is, very highly qualified to know the higher values of life in the Vedic traditional way, so in that way even he is long descended from Advaita, unless he is qualified he cannot be worshipable. Nityananda has no seminal descendants, his son Birbhadra was never married. If someone said he is descended from Nityananda, that means from one of his disciples. These persons may be given some respect, but they are not equal to Advaita.
Letter to Acyutananda, 12 June, 1972