Hi Patrick thanks for posting! If users have been signing in with email/password directly through Lucidchart then you limit the sign on to only Google SSO they'll receive an error when they attempt to sign in with email/password. But if you communicate with them that they will just need to select the Google tile on the login page then they should be able to sign in successfully. Alternatively you can still allow all sign on options if you wish. Integrating with GSuite won't automatically turn off the other sign on options.

As far as licensing once you upgrade to enterprise you will be able to select the Licensing tile in your admin panel and you can select whether you'd like users to automatically receive a license upon joining the account or not. You can also specify what request process they'll need to go through to acquire one. Hope this helps and if you experience any issues please submit a support ticket by filling out this form and we can take a closer look!