1) I haven't read so i'm not sure. Nonetheless, no one is perfect. Sasuke can be caught off guard therefore not have good reaction speed. 2) Why wouldn't they? Naruto and Sasuke are the same age.I'm pretty sure he could've useed Amenotejikara to save 2 people from exploding in the stadium but maybe this isn't in the novel???
And still how did Uchiha and Naruto exist at the same time?
I heard Danzo leaked it in the novels.The Uchiha were still around well into Naruto and Sasuke's earlier years. Everyone in the village also knew what Naruto was from a very early age, minus that he was Minato and Kushina's child it seems. (How you leak that he has Kurama , but not who his parents were is beyond me.)