metadata generation?

Is there a capability to generate the xml metadata needed for configuration?

Not at this point, no. There’s an issue for it in the backlog though: https://github.com/pantheon-systems/wp-saml-auth/issues/87

I don’t off the top of my head, sorry. If you’re a Pantheon customer, feel free to reach out to support and they can point you in the right direction.