Here is another handy plugin that lets you keep data between two separate sites synced. WP Remote Users Sync keeps your users synced across multiple websites automatically. You can use it to import and export users. This plugin supports unlimited sites. You can enable and test various outgoing/incoming actions, including login, create, update, delete, and roles.
You have the option to activate login to see the communications between connected sites. WP Remote Users Sync supports WooCommerce, Ultimate Membership, and Gravity Forms. It syncs your data in an encrypted fashion. This plugin is developer friendly, so you can always add your own actions.