Interchangeability of nominative and genitive forms of Spanish patronymics?

I’m thinking of examples like Álvarez/Álvaro, Alves/ Alves, Benítez/Benito, Díaz/Diego, Domínguez/Domingo, Fernández/Fernando, Giménez/Ximeno, Gómez/Guillermo, González/Gonzalo, Gutiérrez/Gutierre, Henríquez/Henrique, Ibáñez/Juan, Juánez/Juan, López/Lope, Márquez/Marco, Martínez/Martín, Menéndez/Menendo, Muñoz/Muño, Núñez/Nuño, Ordóñez/Ordoño, Ortiz/Ortún, Peláez/Pelayo, Pérez/Pere, Ramírez/Ramiro, Rodríguez/Rodrigo, Ruiz/Ruy, Sánchez/Sancho, Suárez/Suero, Vázquez/Vasco, Velázquez/Velasco.

Filipinos vs filipinos

¿Cómo distinguir a los súbditos de Felipe II en general de los naturales de las islas? Quiero explicarle a alguien que saldrá hablando como un filipino de la primera categoría.

Lexical roots of the eurozone crisis

PIIGS > stable > stability pacts. (If voters consistently elect free-spending hucksters who promise they’ve found a cure for boom & bust etc etc, then isn’t moaning about a democratic deficit as the bailiffs move in ever so slightly pathetic? They had their democracy, but they traded it in for pizza and the X Factor.)

Hot news

Although this fact may not have occurred to American journalists, living in monolingual paradise, it’s hard choosing names in a global market where everything means something bad to someone, somewhere.