@sudeep98 Ohhhhhh!! Thanks. I will give it a try and let you know!
Created a new Test App in FB. Updated the plugin with the new ID, name, and App secret. Saved. Exported.
Updated my XDK. I already had it working as you showed, butt updated with new App ID and name.
It built successfully again, but I got the same error message. "Given URL is not allowed by the application configuration: One or more of the given URLs is not allowed by the App's settings. To use this URL, you must add a valid native platform in your App's settings."
Update 2: Added iOS as a platform and it worked. Thanks so much. On to more testing, but this is last step! thanks again @sudeep98.