Well.....most of Marine aviation is helicopters so I have had a few conversations with some ofmy pals that fly them for the military. I asked them one time about getting a job on the outside world. I said "it must be great for there to be SO many different jobs out in the civilian world flying helicopters" His response was to me - "there are many people looking for each of those jobs and most are coming out of the military with a lots of hours behind them"
Now I don't know anymore about the TRUE situation than you do; but it opened my eyes that finding that job with a new agency, air ambulance, oil rig flying, or police department wasn't going to be an easy thing to do.
Best of luck if you pursue this route without a military background. I'm interested in this charter job you mentioned too that is lined up before you even have a PPL. They must be willing to wait for quite some time.
USMCFLYR