All three were hit, and the boy died.
Leonard Hall Jr., 21, and Marcus Denson, 18, are charged with attempted murder. Prosecutors accuse the two men fired into the backyard thinking that rival gang members lived in the home.
Police say the boy's family had no gang ties.
Prosecutors said that Denson and Hall could face life in prison if convicted. Both remained jailed without bail.
Viewing will be from 5 p.m. to 8 p.m. at Simpson Family Mortuary, 3443 West Manchester Boulevard.
Funeral services will be held Friday at 11 a.m. at the City of Refuge in Gardena, and then the burial will take place at 1 p.m. at the Inglewood Park Cemetery.