I was able to replace the admin password with the default one through the CMS Console under /hippo:configuration/hippo:users/admin. Once I changed that and wrote it to the repository it took a few minutes and a few refreshes of the /essentials tool and then the Template Query Generator tool then stopped showing errors and started showing the document types expected.
Bloomreach, would it be a reasonable change to have the essentials tool prompt for a password similar to the CMS and CMS Console and to require a user with admin role? This would allow at least for custom local setups to to still use Essentials and just to specific a user to be used instead of hard coding local credentials.