HostInterface AuthenticationModes question

The intent is AuthNone is used to allow requests without any sort of authentication. There are types of users that do not want to specify credentials on their host interface, so if the interface is set to AuthNone, the user does not need to provide any credentials for any operations. You might restrict this to a ReadOnly type of access based on the "AuthNoneRoleId" setting; perhaps a user performing GET requests to query system status doesn't want to incur the penalty of authentication over the host interface, but more privileged operations (like modifying user accounts), require credentials to be sent.

The intent of BasicAuth is to show that the interface will accept requests containing HTTP basic authentication headers.

That's right; since in the "AuthNone" case no credentials are passed (meaning no "Authorization" or "X-Auth-Token" headers are in the request), you still need to be able to map the request to a role since there's no account with which to associate the request, which is where AuthNoneRoleId is needed. You can limit the scope of what that type of access can do just like your examples show.