Fortnite Festival Split Screen

Hi yall, im trying to setup splitscreen for Fortnite Festival so i can use a PDP RIffmaster, and a friend can use a Xbox controller for the game. When i try to set it up, it doesn't allow me to use the second player with my controller, nor guitar. Anyone know a fix for this? I made a fresh new account for my friend to use because i cant seem to make a guest appear for the second player.