As for emails, we use the WordPress API without any modifications, I recommend checking out this documentation if you need more details: get_userdata() – Function | Developer.WordPress.org
The verified status of the user is stored in the hp_verified meta field, and the vendor’s status is stored in the post meta field (because the vendor is a custom post type). You can try to change this externally using the WP REST API: REST API Handbook | Developer.WordPress.org