Mark, besides knowing some Parras, I also knew a Grave de Peralta family from the Cuban town of Holguin. You might try to research the two oldest churches in that town for your great grandmother Caridad. She might have been from Holguin. On the otheer hand, I might have some information about both the Grave de Peralta and Parra families in a Manzanillo - another Cuban town in the same region : get yourself a cuban map-- but as the book is olf fashioned and written in a non- historiographical way, it does not have name indexes.
Every time I want to find a data I have to browse again and again; As I am doing my own research, so slowly... It will take me time to find it for you. But I promise to post your name in the monitor, so to remember it.
Nevertheless keep posting it. I knew a certain angelita Grave de Peralta, born ca. 1940. We went to school together.
The churches in Holguin are: The Iglesis Catedral de San Isidoro (Cathedral Church of Saint Isidoro), and the Iglesia de San Jose. There telephone numbeers might be available at the Catholic Archidiosesis of Miami, whose nmber I dont know.
Good luck, Marta