Franz and Frau Schmidt (Gil Stuart and Norma Varden)
Franz and Frau Schmidt are servants in the von Trapp household. We don't learn too much about them, but we know that the von Trapps hide their eventual departure from them so they can (truthfully) claim ignorance.
There's a shot of Franz peering out the window as the family sneaks out into the night. We're not sure why this shot was there. Is he sad? Suspicious? A rat?