MIAMI — One person is dead and several others are missing among a group of people attempting to migrate to South Florida from Cuba on Thursday night, according to federal and local officials. The group arrived off Sugarloaf Key in the Lower Florida Keys on a “rustic vessel,” according to the U.S. Border Patrol. Adam Hoffner, division chief of U.S. Customs and Border Protection’s Miami operations, said the boat capsized and six people were rescued from the water. The dead man was found on the boat, Hoffner said. “All six survivors, who claim to be Cuban nationals, were immediately transported t…