Chris - good article! I'd like to add a couple of things that I have encountered if you don't mind:
1 - No sound from the guitar: check the preamp battery. You'd be amazed at how many guys replace cables, direct boxes, etc. before checking the battery.
2 - Pedals. I don't know why so many guitarists in a worship context insist on using a chorus pedal...constantly. This makes it very difficult to get a decent sound from the acoustic guitar. If possible I convince them to bypass it. Nothing makes a guitar sound mushy, unfocused and out of tune like a chorus pedal.
One time I was on the sound crew at a major worship event in TX. The headliner for the concert was a well known songwriter / acoustic guitar player. During sound check his guitar sounded really buzzy and distorted. We checked everything just assuming that it was an electronics problem. Finally he mentioned that he had recently changed strings and went from medium to light gauge. The lower string tension required a tweak to the truss rod to get the neck relief correct and remove the buzz. So, it's not always electronic!