The twelve survivors were "the Castro brothers, Che Guevara (wounded and bleeding), Camilo Cienfuegos, Juan Almeida, Efigenio Amejeiras, Ciro Redondo, Julio Díaz, Calixto García, Luis Crespo, Jose Ponce and Universo Sanchez."

Some of these I got from Wiki, others I provide the source:

• Fidel later became Prime Minister and after that President

• Raúl became Minister of the Revolutionary Armed Forces (and became President in 2008)

• Guevara had a number of different responsibilities (was very influential in the revolutionary tribunals; became Minister of Industries; and became President of the National Bank, among other things)

• Cienfuegos was one of Castro's confidants but died in October 1959, so he didn't get to play a very big role in the new government

• Almeida became a General in the Revolutionary Army

• Ameijeiras became Head of the Revolutionary Police, but his anti-communism brought him at odds with the party and he was expelled in 1966

• Redondo died in combat in 1957

• Diaz died in combat in the Battle of El Uvero (1957)

• Calixto García eventually became brigadier general

• After 1959, Luis Crespo worked in INRA, the Ministry of Construction, and in Maritime Projects until his retirement in 2002

• Ponce became a higher-up in the National Police, then the military, before eventually becoming president of the conservation and forestry institute of the Cuban government

• Sánchez became was influential in the revolutionary tribunals, and also seemed to play an important role in the government (until he shot a Minister in the head for badmouthing him)

EDIT: So to sum up, the ones who survived became very, very influential people in Cuban politics, for the most part