I wasted a lot of time trying to buy an audio panel from RST Engineering. They don't always stock what they advertise. By the time they had the panel back in stock, the void date on my check had expired. No attempt at discussion with the owner was fruitful. My advice: avoid these people. They have a good product, but it isn't worth the hassle.
I drew the new schematic around an MGL comm transceiver. It has a built in intercomm capability, sot he audio panel is really just the ability to switch between to comm transceivers, and add aux audio from multiple sources. It looks like it will be a totally passive box.
The hardware drawing for the chassis will come later.
