My initial thoughts to Alex’s first post; I’ve just seen the second post.
Asterisk (*) below indicates a proficiency/skill selected with a non-Thievery power.
Expeditionary
a looter of tombs and delver of dungeons [optimized for dungeon thievery]
Climb Walls*, Hear Noise*, Find Traps, Open Locks, Remove Traps
Note: I’m envisioning the Expeditionary as a specialist, non-melee combatant, thus no Backstab, Hide in Shadows, Move Silently. The difficult to spot power might be appropriate as low cost stealth.
Ruffian
a cut-throat and killer [a sneaky damage dealer, similar to the 3.5E rogue]
Climb Walls*, Backstab, Find Traps, Hide in Shadows, Move Silently, Open Locks
Note: Climb Walls, Find Traps, and Open Locks to reach a well-protected target.
Scoundrel
the gentleman-thief [optimized for disguise and charlatanism]
Hear Noise*, Hide in Shadows, Move Silently, Pick Pockets
Note: Hear Noise because of Carousing, and Hide in Shadows because of Spying. Pick Pockets suggests many Freebooters choose the less deadly path of Scoundrel, per the rulebook comment “this skill is the bread and butter of nonadventuring thieves.”
Wayfarer
a bandit, highwayman, or scout [optimized for wilderness thievery]
Backstab, Hear Noise*, Hide in Shadows, Move Silently
Note: Hear Noise because of “scout” and Carousing. Hide in Shadows because of Spying, and Move Silently because of Smuggling. A Wayfarer might select Trapping proficiency to “detect and disable simple wilderness pits, snares, deadfalls, etc., as a thief of his class level.”