Researching Scown of Cornwall England

Lillian Grace Scown, b. 1896 in St. Mewan, London, England, is my paternal grandmother. George Scown, b. ~1871 in Truro, Cornwall, is her father. He was the owner of a pub, The Bricklayers Arms, on 389 Cable Street in London from roughly 1915 through 1922.

Lillian Grace Scown, her husband Jose Policarpo Nunez, and their two small children, Lillian (b. 1918) and Joseph Nunez (my father, b. 1916) emigrated to New York in 1919.

I have birth certificates, immigration manifests, marriage banns and other documentation relating to all the persons named above. I am missing information on George Scown's parents, and on his (first?) wife, Mercy, who is Lillian Grace Scown's (b. 1896) mother.