Glad you got that figured out Grant.. MrCase, I still owe you the docs. We are still house-hunting in the town we are (still) planing on moving to and it's quite a hassle... Hopefully one of the houses we saw will work out....
anyway, I got a PM about grounding, and I realize the schematic seems not to match the board. It looks like the audio I/O on the schematic shows XLR pins 1 and 2 instead of 2 and 3 but that is actually the pin numbers of the Molex connector and do not represent XLR pins, and is quite confusing. I'll try to edit that to show 2 and 3 instead.
As a general rule with these, I don't connect Pin1 to the audio circuit at all. I'll either run the XLRs to the case tab on the XLR (make sure this has a secure connection to the case) or run each pin1 to the "star ground." You can do whatever you wish, they should both work about the same. Another option would be to run the input XLR direct to the case and then output XLR pin1 to a SPST switch, then to case ground, so you can lift the ground if need be.
As far as grounding the PCBs, I run 2 ground wires from the audio PCB to the PSU PCB, one for the power/audio and one for the LED rail. I then run a wire from the PSU to case ground. Case ground is permanently connected to AC ground, and ideally you'd stick a switch between the PSU and case ground in case you ever want to lift this ground.
There are other ways that might work, but I think this should work in most situations. If you decide to not to use a fourth rail for the LEDs you can just jumper the LED rail to the positive rail and the LED ground to the other ground and run only one wire from 312 to PSU.
hope that helps!