1) No? Orange is owned, white is not owned. Empty stuff has no own color, it remains orange or white upon being owned or not. It only changes from orange to white if the owner dies (and as far as I can tell is slightly buggy in that regard in that it doesn't update till reload or interaction instead of after that NPC is dead).
Feel free to correct *me* though if I am wrong here, anyone...

2) Yup, though it seems opening and closing inventory will fix this 'stuck' behavior. I only notice one such item at the marketplace, and that's actually an item I sold, and shouldn't even *be* in my inventory in the first place!