Pressure problem, 1 atmosphere to vacuum
Lets take your questions one at a time.
1. The pressure in the box will be 1 atm., whatever the volume of the box, as long as the temperature is the same as when sealed.
2. If you lower the temperature, use Charle's law PV/T =Constant, to work out the new pressure. Note that T is in absolute units, not deg.F or degC.
3. The dimensions of the box will determine the bending moments on the sides. The strength of the materials and the wall thickness will determine whether the box will burst or not. Note that the pressure 'on the lid' remains whatever you calculated in step 2.
4. The elevation makes no difference to the result from step 2.
5. But the strength of the materials could be affected by the temperature in space, you need to check this out.