Three brothers whose exposure to AIDS made them pariahs in their rural hometown enrolled in a new school without incident. Officials at Gocio Elementary School in Sarasota, Fla., reported that 120 of the 615 pupils stayed home, and up to a dozen were withdrawn. The usual absentee rate is about 3%. Ricky Ray, 10, Robert Ray, 9, and Randy Ray, 8, attended school in Arcadia, Fla., for a week under federal court order. A boycott emptied classes, and telephone threats were made against the school and family. The Rays left Arcadia after a fire gutted their home.