Good questions. Remember that we're thinking "fits in a shoe box" which limits our options.
Compared to octagonal pry bars, I find a flat bar to be far more versatile for demolition (and nearly everything else. The ones I consistently reach for are 18" long (every extra inch of leverage counts).
This shows the general concept (not a brand recommendation). Many manufacturers make them.
A 10" vise grip with wire cutter is the original heavy duty multitool. (The 7" ones are excellent also, but the extra 3" of leverage makes a surprising difference.) In a pinch, it does nearly everything involving demolition or repair, multiplying the power of your arms my many times, and the grip of your fingers by 1000. I have yet to break one.
Edit: I suspect edged tools like hatchets would be banned on campuses. A hammer with a ripping style nail puller may or may not sneak by.