Funny, that's one reason I would expect GWB to leave it alone. The same goes for your #3. He seems to take great pains to ensure no one has any grounds for accusing him of a personal attack on Bubba & Co. I suspect Bubba knows it and takes great pleasure in it. It's a fundamental difference between most Ds and most Rs, and the worst of the Ds exploit it at every turn.
Your #2 might be a good reason but, I seriously doubt it's enough to persuade him to open it.
Even if GWB is very interested to know whether TWA 800 was an act of terrorism, that is a separate issue from whether We The People "need" or "deserve" to know the same at this juncture.
But again it's really just wishful thinking. My dream of seeing the Clinton's doing a perp walk for all their crimes will never happen.