It's definitely a close call between press and bench press.
Bench press might be the winner because it's a bit less technically demanding and doesn't engage the lower body as much, even if you're using leg drive. But a strict press is less easy to cheat on the ROM, plus I would think traps, abs, erectors, serratus are more engaged than in the bench, but it might be a bit trickier to teach in a standardized test.
I would say no to muscle ups because they are too technique dependent. I like the idea of pull ups, although it's a bit tricky to figure out how much weight you're really lifting between people of different builds/bodyweights. Wonder how many pull ups Maddox can do, I saw Bibby and Brian Shaw doing them and it was impressive considering they're 400lbs+.
But overall I'd say bench/press/pull up (if you can determine max weight, not reps) would give you a good average.