Well, we have been bombed with parallells from all sides. XD MinaKushi, ObiRin, even DanxTsunade. That's all, because Naruto hasn't really interacted with Sakura personally. Because they are in a war, they need their mind set on the battle.
Nagato's parents may have known and they were probably refugees, but I think the clan scattered out and tried to blend in wherever they escaped to. His parents died early, he was probably too young to know.
Well, that explains the Nagato part, yes. However, Karin is still questionable, but again, I think she doesn't know either. When she finds out, she can connect the dot with Naruto, now that she knows him. It's really puzzling.
While no real defining moments, there are more parallels to really make NS too hard to ignore, especially one is too much identical despite its fate. Otherwise, should have made a parallel with NH. It could get worse if Hashirama parallels as well and so far, characteristic and historical events, it is suggesting it.