OWA and WAP with ADFS and delegation

I have 2 questions.

I am attempting to get WAP working with OWA in my test environment prior to moving to prod.

My WAP server is in the DMZ and not a member of a domain.  I have ADFS set up and verified to be working.

First question:

Pointing the OWA DNS record directly to Exchange is working with ADFS.  However, pointing to WAP I get WrongAudienceUriOrBadSigningCert error after entering credentials into the ADFS login page.  I see steps in the documented process about setting delegation to give the WAP server "PrincipalsAllowedToDelegateToAccount".  Since the WAP server is not in a domain how would I go about this?  Maybe this isn't the issue?

Second Question:

Is there a way to specify a default authentication domain in ADFS so users do not have to enter DOMAIN\USER in the OWA/ADFS login?