Those are the types of things developers simply don't have experience using. And if Kubernetes tries to replace all of those it will become the new OpenStack.
Yes to all. The most difficult thing is persistent volumes, but leveraging things like Heptio's ark allow you to send them to an alternative storage class. It's awesome stuff.
Well, that depends where those resources are running and also depends if you're leveraging persistent storage in k8's. All the routes/firewall/dns etc. will be preserved in the event a data center is nuked. Like I said, k8's is replicating your entire system behind the scenes.
There's a lot more to replicate than just the bits in the apps.