The title could refer to a quote by Gandhi, "...the still small voice of conscience," or a quote from Carlo Collodi's Pinocchio, "A conscience is that still small voice that people won't listen to."
Emma asks Henry if Marco is Archie's father, even though Marco told her in Pilot (2011) that he doesn't have any children; it is not illogical to assume it's an effect of the curse for Marco to have forgotten that he has children.
Archie is generally short for Archibald, a name meaning "bold" and "genuine," sometimes given as "truly brave" (from Old High German "erchan," meaning "genuine," and "bald," meaning "bold").