1/2- Even when hosting the kyuubi avatar, he was able to react to obito's speed. Obito caught both him and sasuke, if you don't remember. And as I said, it's because he is obito, the jinchuriki of the juubi, fastest shinobi shown in the seris without space time ninjutsu. In any moment I said naruto is faster than obito.
Besides, naruto can cast out the cloak anytime, returning to his "human form", abd being able to acess his full speed.
3- They should be able to sense it(as sensing obito's movement was a fact, it happened, naruto would so be able to sense amaterasu as well), and as they can return to the "human form", they might as well dodge it. Besides, there is the other defense mechanism I mentioned(using the chakra projections) which is another way to evate sasuke's enton.
Agreed. However, bijuu damas have a great chance to damage sasuke's susanoo, and the clones can use them long-range, as well as defend themselves against amaterasu.
4- Honestly, it's debatable. Bijuu damas are fast, and continous bijuu damas too. If sasuke is surrounded by naruto's bushins, and they use such atack. It would be 20, maybe 30 bijuu damas if we inculde the original naruto, going at high speed towards sasuke. He would have to be fast enough to make a counter for all of this bijuu damas before they get too close and explode right in his face, or close too him which could still harm his susanoo.
Locate the position of 30 chakra bombs at high speed coming from all directions and counter all of them in no time(You also have to remember that bijuu damas aren't easy to be stopped) is something sasuke might not be able to do.
If Naruto was able to 'react' to Obito's speed then he wouldn't have been caught. I'll say it again, while hosting the entire Kyuubi's shroud Naruto's speed is nothing spectacular. Leaving the shroud to access this speed will amount to nothing as compared to the Perfect Susano'o a BSM Naruto without the shroud can do nothing to affect Sasuke as his arsenal is limited to Rasengan based offenses, Chou mini Biju Dama and chakra arms. None of this is even phasing Sasuke's defenses I'm not disagreeing that they would not be able to anticipate incoming attacks, I am saying that they would only be able to evade if they are not hosting the entire Kyubi Shroud. Even though Sasuke's Susano'o is damaged, it can be immediately repaired at will. There is no need to speculate on the number of clones and attacks. The Enton-Senbon would not cause the Biju-Dama to explode as it does not add or subtract from it's composition: a specific ration of Black and White chakra. It is the reason why Madara was able to balance the dense entity on Susanoo's swords without an explosion. Which leaves the idea of the Biju-Dama exploding near Sasuke a moot point. The initial claim that BSM Naruto is > PS Sasuke can be labelled an assertion and not fact.