I don't think this ISabel and Isabel Velasco de Mendoza are the same person. Because The velasco one was married to Luis Carillo. Isabel Velasco would have been born ca. 1565, our Isabel should have been born ca. 1535-40 at least. Francisco, Marqés of Almacan was born ca. 1530 so these two are not the same people. I think were better off with Diego Hurtado de Mendoza, who settled in Los Altos.