As soon as i got a link between Ferdinand and Maria Louise of Hesse-Kassel, wife of Johan Willem Friso of Orange-Nassau i knew he was a direct ancestor of all reigning monarchs of Europe with the exception of His Holiness.
And the House of Montenegro .
Should King Danilo had had issue with Jutta-Militza of Mecklenburg-Strelitz and that box could be ticked too.