In response to your first point: You are correct in that moderators are not privileged to insider information. However, they do have a bit of a lead in that they have to know when something is coming up so they can prepare and know appropriate procedures. Also, they are under the authority of the administrators (who do have insider information) and the moderators take their cues from them. From all we knew, the admins could have instructed the mods to sticky this thread after a certain date.
In response to your second point: Although the Imperial Library is supplying the trivia questions, it surely couldn't have been the IL who forced Bethesda into doing the TESting Your Knowledge, which means that Bethesda is the one behind it. It isn't a requirement of the Imperial Library to know what Bethesda is doing for them to supply trivia questions.
Finally, the existence of this thread does not guarantee anything - I'll give you that. However, due to the presence of administrators and developers here (and that they haven't killed it) leaves me to believe we may have merit for suspicion.
I think the trademark renewal issues do constitute good evidence that something is happening, and the book certainly suggests they aren't giving up on TES just yet.
It's possible that the moderators have been informed by the Admins, and it's possible that someone from Bethesda contacted the good folks at TIL to come up with trivia questions, all the while having in mind revealing something when the trivia questions ran out. Those are both possible, but I don't see any hard evidence for them. It's just as likely that the moderators have maintained this thread so they don't have to deal with multiple threads on the same topic, and that someone from TIL suggested the trivia contest to someone at Bethesda, or someone at Bethesda contacted TIL about trivia, simply because he/she thought it was be cool, or needed a way to unload extra books, or whatever. My point is that there are lots of potential explanations for TESting your knowledge and the fact the mods have maintained this thread, and no hard evidence that they mean a reveal is on the horizon.
Having said that, again, the trademark renewal issues are suggestive.