Hmmm you'll have to be more specific because technically everything is a thing. Hence the term "everything" But if you are referring to the rules, as in it must be a "person (NPC), place, or thing," then I can say that no, it is not a person (NPC) or a place, so in that case, yes, it would be a thing.
Nope, assuming you meant when OoW was the most recent expansion, from its release up until the next expansion
Want to speed dial this? The same question is asked for DoN and DoD. Was it introduced to the game in DoN?
Sure. The rule is one question per person, but you're the only one playing right now anyway. No for DoN, yes for DoD. Yes, it was introduced as part of or during DoD [being the most recent expansion]