Guest Stars Janel Parrish as Mona Vanderwaal Keegan Allen as Toby Cavanaugh Lesley Fera as Veronica Hastings Tammin Sursok as Jenna Marshall Brendan Robinson as Lucas Gottesman Nolan North as Peter Hastings Brant Daugherty as Noel Kahn Eric Steinberg as Colonel Fields Charles Hittinger as Sean Ackard Diego Boneta as Alex Santiago