General:
As far as I know your "thieving" skill has something to do with sucess of "talking way out", but in G3 i can't understand the complete Thieving-"tree"…I love to sneak around and steal things in games, but in gothic there is no need for thieving (my oppinion).

@Question:
I haven't played 1.12, but without that patch you can simply provoke them, lure them out of the city(out of sight of any npc), knock him down (not killing) and everything is forgotten…working if you are wanted for murder too
And you mentioned white to orange names…I know no difference between NPCs with white or orange names…only green and red are interesting for me

But if it's changed with 1.12…can't say that - G3 is in my shelf and I'm playing G1 at the moment