Take rogue and halfling. Take the thief subclass. Dump strength. Put as many points as possible into dexterity. Pump moderate points across Wisdom and Charisma to make him clever and persuasive. Take stealth, performance, sleight of hand, deception, and persuasion.
If you have space for more skills, consider the following:
Insight (Wisdom roll)
Perception (Also Wisdom roll)
Acrobatics (Dexterity roll)
Investigation (Intelligence roll)
