Hello, I found this information which I would like to share, in case it is useful to someone.
I know that General Hernandez had descendants in the US, I don't know if he had any in Cuba.
Regards, Teresa

http://search.ancestry.com/db-conbio/P414.aspx

Biographical Directory of the American Congress
Viewing records 4,131-4,140 of 9,953 total records

Biographical Directory of the American Congress, 1774-1949
Biographies
H
page 1303
HERNANDEZ, Joseph Marion, a Delegate from the Territory of Florida; born in St. Augustine, Fla. (then a Spanish colony), August 4, 1793; transferred his allegiance to the United States; upon the formation of Florida Territory was elected as a Delegate to the Seventeenth Congress and served from September 30, 1822, to March 3, 1823; member and presiding officer of the Territorial house of representatives; appointed brigadier general of Volunteers in the war against the Florida Indians; entered the United States service and served from 1835 to 1838; commanded the expedition in 1837 that captured the Indian chief Oceola; appointed brigadier general of Mounted Volunteers in July 1837; unsuccessful candidate of the Whig Party for the United States Senate in 1845; moved to Cuba and engaged as a planter in the District of Coliseo, near Matanzas; died at the family's sugar estate, "Audaz," in the District of Coliseo, Matanzas Province, Cuba, June 8, 1857; interment in the Junco family vault in San Carlos Cemetery, Matanzas, Cuba.