Wagner Moura is Brazilian and had to learn Spanish to take on the role. His mother tongue is Portuguese. Incidentally, the opening theme is also sung in Spanish by a Brazilian musician, Rodrigo Amarante.
Major Wysession is actually a Colonel. Early on in the season, his eagle rank insignia is properly adhered to his uniform shirt collar. Later on, it is woefully misplaced, in two ways. A United States Marine Colonel would never have his rank insignia, or any other medals improperly placed on his uniform.