#1. 8,000 feet is the standard cabin atltitude for most commercial (transport category) airframes. This is a derivative of the cruise altitude and the differential pressure. 7.8-8.3 PSI generally.
#2. Some cargo compartments are NOT pressurized, they lie outside of the pressurized vessel bulkheads.
#3. The contingencies, such as a decompression, regardless of how rapid it is, are what are planned for when deciding what can and cannot be carried. Flying is all about planning for the unexpected, which is why any transport category aircraft must have redundant systems whereas general aviation aircraft do not.
SO did the OP ever place the call?