You make no sense. Its Area of Effect is large enough to hit EVERYTHING AT ONCE. He doesn't need to focus on one target. Once they've been slashed enough they will become so small that they are useless in defense and offense. Besides, their attacks are useless against PS so whether they are ignored or destroyed it doesn't matter. Nagato isn't getting close period. The Five Kage were tossed backward by a slash that wasn't even aimed directly at them, Gedo Mazo's feats make it useless against PS and Nagato can repel one slash with ST but he can't repel the other one due to the 5 second interval.
PS is armor for the Kyuubi. Kyuubi has no effect on the durability of PS.
Gedo Mazo does not match PS's size, the Mazo isn't even as tall as a Mountain unlike Perfect Susanoo. Neither are the summons and their attacks are completely irrelevant as they lack the power to even scratch PS.
Shinra Tensei has a 5 second interval. 1 slash is blocked and the next one kills him.
we will never agree on the PS+KYubi thing. I personally believe Madaea had to combine with Kybui or he would not have survived. The PS armor melded with Kyubi's skin. Its not like Kyubi was wearing PS's robes. They combined.
1 slash is blocked, the sword is pushed away or perhaps Nagato goes crazy and knocks PS over with the ST. This is enough to give him time to touch and eat it. And yes, he can do that, he obliterated a whole village remember.
PS slash attack is simply a slash attack. It only affects the arc which it swings. If for example, it tries to slash at a bird, and the bird goes higher, it won't get it, since the bird would have escape the arc. Its not like it shatter those mountains entirely, its merely like a very long sword. Hence it can be dodged.
The dogs are indestructible. Naruto's RS(and I beg you to recall that the RS is slicing the ten tails to bits right now) didn't do ANYTHINg agaonst it. If the slash hits the dogs, it may send it flying but it would slice though, as Rasenshuriken couldn't AT ALL. The dogs can keep fighting forever.
Also, recall that Bansho ten'n allowed Nagato to detach a rock from the side of a clifff face and use it to smashsix tailed Naruto whilehe was making bijuudama. Nagato can merely use that same level of control to keep Susanoo's arms from moving. Then eat all the delicious chakra.