I dunno why everyone is making such a big deal out of it, Shiki's sister has already, to some extent, nullified the threat of death. It might not be as strong as hers, but it makes sense that other kemono could also perform similar things with their powers.
That said, as much as I would've liked to see one of them die, it would be too early, I feel, for either of them to kick the bucket just yet. We've only seen them once, and it was in combat at that -you've read these sorts of superpower fighter manga, we all know it's super likely they'll show up again later, possibly as allies after some evil, more dangerous third-party enters the fray.
Fuck, I kinda hope that doesn't happen at all, Inari being an indirect, controlling villain is pretty cool.