I can say that this is the best chapter I have seen in the last few weeks. It was heaven time Kishi shows to the people that they need to educate themselves, and learn some logic. Yes, no Yin Kurama is going to be sealed in Naruto because it does not make sense at all. The manga has shown that Naruto has a huge power inside him that he never used due to kyuubi, and we have to see that power. We have to see the meaning of the whisker on him, and what the power of Rikudo was before he became Juubikudo.
Next, I think Kabuto is still the mysterious person. It is normal that Tobirama asked because he never saw Kabuto. Second, it is normal that Karin did not recognize him because he is in DSM mode. It is even easy to see that Kabuto is pumping natural energy all around him. Besides, to break out of Izanami, Kabuto may have surpassed the level he was at during his fight. This is not actually a theory, but something I would like to see. How Orochimaru will do when Kabuto will stand on his way (because Oro betrayed Kabuto).
The least I can say is that Kishi is following the rule of good writing - that is to make the reader believe that there is no hope in beating the bad guys.