I think what Kay is picking at is the order of operation of everything, whether you explained it or not.
If you want everything (bijuu, all his knowledge, his very soul if you like) then there is a process for it is what she's getting at.
Now then, technically there is no rule currently implemented that says that you can't get the bijuu from a dead host. For the sake of arguement, let's just say that doesn't matter in this case (next one will be next paragraph). First, you get all of his knowledge via human path. Then use the rinnegan technique to bring him back and get his bijuu. That'll kill him again, so then you can just use edo tensei. Or, use edo tensei instead of rinnegan technique.
For case # 2 (killing host screws it over), you will need to extract bijuu first, revive him via rinnegan technique, weaken him again (a snap since your jujutsu should still work I think), then use the Human path to extract all knowledge from him and take his soul. That'll prevent him from being revived by anyone except you.
In either scenario, if you bring him back via the rinnegan technique, you may have to weaken him again, seeing as that restoration seems to have a mass body healing effect, since people thrown about with broken bones and ribs and death-injuries can toss Naruto up into the air and cheer him on after he returns.
Kay, my guess is that the ability for the snake shed is not derived from his Snake Sage Mode, largely becuase Sasuke was able to perform it (after absorbing Oro, and knowing absolutely nothing (most likely) about senjutsu) during his fight with Itachi.