DeletedUser119 With GOS's Android Auto, will I be able to do this with YouTube or Newpipe
Not with Newpipe at least (maybe I'm wrong). Apps have to be installed from Google Play to be detected by Android Auto, and Newpipe isn't allowed in Google Play.
Also, with GOS's "charging- while locked" pin security, if I lock the phone will it shut off my video or audiobook?
You mean the USB port setting? The setting says "If the port is already plugged-in at the time when the device becomes locked, then activation of charging-only mode will be delayed until the port is disconnected."