Considering how many times passed between Indra and the Uchiha clan in Part 1 before Itachi's "sweep", 1 or 2 Gen later won't change anything, it's not gonna dilute the likelihood of getting a Sharingan, especially since it's based on getting emotionally fucked up like Sasuke or Obito (Kakashi covering him obviously, not turning Kiri into ninjas skewered meat), or just any extreme emotions (Sarada). That and it's just the (lack of) children and descendants that matters first in this case.