I recently had my car overheat due to a hole in the house and caused my car to pop a freeze plug. I let the car cool and tried to restart (before finding the missing freeze plug) and it would not crank. Could this be because of no pressure in the cooling system or a sign of a much bigger problem?

 

It could be a sign of a much larger problem. The cooling system pressure is not monitored on these cars, and there is no pressure anyway before the car is started if it has cooled off completely.
When you say would not crank, do you mean literally the engine would not turn, or just that it would not fire?

 

It tries to turn over but doesn't start. I haven't tested the cylinder compression yet but I was hoping there was a reason for no-start conditions other than the head gasket being blown... It's not looking good.

 

I would pull the spark plugs and see if they are wet, and if they are, is it fuel or antifreeze?