Thievery is largely a thematic thing. I had an extra skill from being Eldarin, and the other characters have healing etc covered. That and, with my dm's consent, I want to set my character up as a bit of an Alchemist later on - depending on how the campaign unfolds - and craft several useful items (i.e. Alchemists Fire/Acid/Whatever ammunition etc - not terribly effective perhaps, but terribly fun.)
In the meantime, even regardless of whether I can get Alchemist or not, Thievery suits the 'skulker' background I'm working on and can, in some instances, be quite handy

Oracle - what would you suggest instead of Shadow Wasp?

Carpe - I think you are right about the Longbow. I'll look into that.