Maybe you already have the info you were looking for, but here are some bits I have:
John J. Mulkern was the son of Bryan Mulkern and Catherine McGarrigle. As you know, John and Mary got married November 10, 1917 in Los Angeles. They were the parents of Mary, John and Frank Ignatius Mulkern. Mary was the daughter of Ignacio MacManus-González and Silveria Olivares-Zuloaga, the three of them were Mexicans born in Chihuahua, Chih.
John and Mary got divorced December 29, 1928 after a big incident that even made the papers of those years.