@johnathon

One approach would be to append the parameter idp_hint to the login URL to redirect a user to the appropriate IdP login page. Please read the hints section in our documentation for more information.

Another way to disable the password and email login for a user would be to set their password to a random 25-character string. This would make the password essentially impossible to brute force and thus impossible for them to log in via the hosted login page.

You can use a 'soft delete'.

Whenever you delete a user with the API without using hardDelete=true, the user is not able to login, but will still be visible in the API and the management UI.

See https://fusionauth.io/docs/v1/tech/apis/users/#delete-a-user for more.