I would first change the pcv valve.Its cheap[ and would cause oil to leak in alot of places because of crank case pressure.
100000
Seems the flexpipe leaks at the ends...
If you have leaks in a water bottle rocket, the pressure will quickly escape along with the water and the rocket won't be able to reach as high an altitude as a rocket without leaks.
The common vacuum leaks on the 2004 Trailblazer are usually from the dashboard. It is therefore important to service them regularly.
The most common place for oil leaks is the sump/crankcase cover gasket. A torn gasket will allow oil to escape. A common cause could be a blown head gasket putting too much pressure in the crankcase.
I'm pretty sure it's common
These are common for oil pan gaskets, if the oil level is a quart low it most likely isn't high enough to leak out the gasket
There's really no link between the two events.
A crack, crevice, fissure, or hole which admits water or other fluid, or lets it escape; as, a leak in a roof; a leak in a boat; a leak in a gas pipe., The entrance or escape of a fluid through a crack, fissure, or other aperture; as, the leak gained on the ship's pumps., Leaky., To let water or other fluid in or out through a hole, crevice, etc.; as, the cask leaks; the roof leaks; the boat leaks., To enter or escape, as a fluid, through a hole, crevice, etc. ; to pass gradually into, or out of, something; -- usually with in or out.
crank seal
no
Yes, IF the combustion chamber and flu system leaks and allows combustion gasses to escape into the area where you are.