It’s early and I can’t fully discern your question:
WordPress has a wp-config.php file that contains your settings saying which database/host/username/password to use.
You can edit that file if you want to use a different database.
Database Hosts are extremely flexible and interchangeable. In fact, it really doesn’t matter which database hostname you use, as long as it’s any one of the ones listed in the DB section of the panel:
Since it’s WordPress, don’t worry about breaking the One-Click feature for your WordPress. I recommend that you manually update the wp-config.php file listed above and Remove (not Delete!) that One-Click entry from the panel here. I recommend this because WordPress has an excellent built-in update mechanism that I use instead of the One-Click mechanism.