I just ran this encounter last night and tried a variant of your twist.
Spoiler:
The 3 faceless stalkers were disguised as 3 beggars. Since the house looked like it had been ransacked, I figured it was appropriate. One of the faceless stalkers (with a level of rogue and dual-wielding short swords) was a gnarled old woman and upon being threatened by the LN Order of the Nail wannabe in the group, collapsed on her knees before the lightly armed ranger, pleading for mercy. She managed to get the jump on him as he raised her to her feet and so the fight began. The group were easily convinced that these were just 3 beggars trying to find a roof over their heads. It was awesome.
My PC's just captured Nualia and they are planning on taking her back to town to turn over to Belor and Deverin. Any ideas on what they would do to Nualia? Would she be sent off to Magnimar for trial, or would she just be tried here in Sandpoint?