A little inside joke: Sashsa asks Lizzie, "What accent were you faking -- Australian?" Lizzie, of course, is played by Bojana Novakovic, who has lived in Australia since the age of seven.
Both Alan Cummings (Dylan) and Bojana Novakovic (Lizzie) speak in their native accents in this episode when undercover. Cummings is Scottish and Novakovic grew up in Australia.
Harpocrates is the Greek god of silence and secrets.
Error: the guest complains at the fancy hotel that they got him opera seats in the "mezzanine" instead of the "house seats" he asked for. It's likely he meant he wanted seats in the stalls, as house seats are the free tickets held and distributed by the venue (the "house), not a section of seating.