“scouts.” More literally “watchmen” or “guards,” but these were the watchmen of the Israelite invasion force.
“we will deal mercifully with you.” The verb hesed is hard to translate here. It can have the meaning of mercifully, especially in light of the fact that the rest of the city was destroyed. It can also mean faithfully, meaning that the man would not be double-crossed after showing the people how to enter the city.