Hi @capndave
Thank you for posting your question on the Auth0 Community!
I am a little bit confused from your post, currently do you have issues in auto-filling the email or password field?
As I can see in the code provided , if you pass the login_hint in the parameters of the redirect url, the email address should be filled in, as seen in the example below:
https://[Tenant].auth0.com/authorize?client_id=[Client ID]&response_type=token%20id_token&redirect_uri=https://jwt.io&scope=openid&login_hint=user1@gmail.com&state=1234&nonce=5678```
However, if you are having issues with auto-filling the password, I believe that feature is not available at this time while using the Universal Login and only the prefill option would do the trick which is only available for Classing Login.
You might want to look into Password Autocomplete in our documentation which I believe suits your use case.
If you have any extra questions on the matter, feel free to leave a reply.
Kind Regards,
Nik