Also, those that know these type of things, was the flight path they used necessary for orbital insertion, or did they specifically pick that path to piss in the wind?
Well that depends upon the inclination of the orbit they wanted to achieve. Still, the path they picked was about the best they could manage. If NASA or ESA were to launch from there then they'd probably have picked a similar path.
To be honest, North Korea did everything right in trying to appear like a sensible and responsible launch nation. They notified the correct authorities and they described the launch vehicle and debris zones in sufficient detail as to provide warning.