Yet that failure defeated the entire world.Madara is kinda the only failure
9 Bijuu, Naruto, Sasuke, Sakura, Obito, Kakashi, 8th Gate opened Gai, Hashirama, Tobirama, Minato Tsunade, Oonoki, Gaara, Lee,Ay, Killer Bee and the rest of the NV with Infinite Tsukyomi.
1. No, Itachi planned to die by Sasuke's hand, he could've easily negged sasky from the beginning.1.Sasuke accelerated the process. Just like against Danzo, he didn't land a finishing blow but he's still responsible for his death.
2.Sarada is an UCHIHA who wears glasses for a reason. MS confirmed.
2. No, she is a fodder haruno and doesn't have a sharingan, she is not an Uchiha unless she has a sharingan.