Back when they honored DCist by performing at our second Unbuckled, Olivia Mancini and Randy Scope had Housemates and bandmates. All their Housemates were bandmates, but not all of their bandmates were Housemates. Since then, Washington Social Club called it quits, leaving Mancini and Scope with fewer bandmates, but more time for the Housemates, who will be playing the Black Cat this Saturday night. There, they will debut fresh material for D.C. fans in support…