Semi-success! And fail!
I've moved all light processing into a separate Arduino Nano board that I had lying around and it worked a treat. Rock solid lighting and freeing up resources on the Chipkit for gameplay!
But I accidentally loaded the lights in the wrong order, enabled some lines that probably should have stayed off (most likely shorted ones... Maybe they were the problem with the lightboard in the first place?) so now the lightboard is once again acting up, and it's going in the dumpster instead.
Two options exists:
1) Recreate the board, twice the scale but still with 96 "inputs". Expensive and very hard to solder without making mistakes, even with the larger spacing. Also, did I mention it's expensive? If I need to add a resistor, make that 96 resistors. MOSFET's? Make that 96 of 'em...
2) Create a matrix board instead. A LOT cheaper and quite easy to solder. I'll be able to visually debug the lines by using led's on the row and column MOSFETs. The downside is that I'll have to re-do ALL the lights wiring, at least most of it anyway. Each light needs to get a new ground and power line. The old board sunk current, while this will be providing instead.
I'm thinking about doing it the proper way now with a matrix, since that's how real machines does it. It also allows for easier troubleshooting and replacing of bad components. But I'll probably won't go down the PCB route this time either, the risk of me making a digital error in the drawing as a first-time user is too big. But we'll see...
Oh, and I'll be replacing the three MP3 Triggers with a single WAV Trigger.
The follow-up product is the same size, but allows for 14 simultaneously mixed/individually running stereo tracks and a bank of 1000 files, including individual settings for crossfades, looping, volume etc per track. This will allow me to properly play sound and music instead of continuously compromising which effect should have priority over the others etc.
It will also free up two hardware serial lines (one's already in use by the Nano) for additional things, such as a hardware clock countdown for timed modes etc. Great stuff!