So I finally had some time to get back to this project. I have updated the wiring in my controller based on almost all of the suggestions I got here - thank you again for taking the time to counsel a newbie.
The good news - almost everything is working. My PIR consistently triggers the Arduino. My audio plays when expected. All four relays trip and the lights attached to the relay-controlled 12v output come on when I want them to.
The not quite so good:
As Paul_B predicted, I am having a problem with the GFCI. It trips as soon as the relay that provides power to it turns on. The GFCI is integrated into the outlet I'm using. I am going to test with a regular receptacle without GFCI. If that works then I may just go with that instead of bothering with GFCI.
Thanks again,
Mike