@Kaido:
I wonder if Kanjuro let Kiku strike him down. We saw in his flashback that he was pretty much suicidal and wanted to die after he had fulfilled his mission as a Kozuki spy. If he survives, and Orochi is now dead, the stage is set for him to convert back to the protagonists' side.
I can't see Kanjuro surviving, but even if he somehow did, any "conversion" back to the side of the Kozuki loyalists would ring hollow. The duration of his infiltration and undermining of Oden and the Akazaya's goals, and the ease with which he tossed those bonds aside the moment Orochi told him to, render Kanjuro utterly untrustworthy.
Even if alive, the only role he has now is that of a Kurozumi avenger, which at best would pit him against everyone once he learns that Kaidou offed Orochi, or at worst set him on a course to hunt down as many Kozuki loyalists as he can before he dies (possibly starting with the seemingly defenseless Hiyori). And honestly, now that they know what his powers were capable of and how thoroughly dangerous to their cause he was, I can't see the Akazaya making the mistake of not striking Kanjuro down for real when given the chance - or more to the point, making absolutely sure that they'd struck a lethal blow on his actual body before letting themselves mourn.
If anyone manages to survive their death scene, it's probably Orochi himself - we've seen the head a couple of times, but not the body, and his Devil Fruit giving him multiple heads is just too perfect for surviving decapitation, even if it means he's unable to return to his human form ever again. And even then, it's a long shot.