12V Gremlins - 2005 Trim 5

So let's start this the right way.

No. I don't have Techstream. Yes, I need it. It's on the way. But I need my car Tuesday morning, and it's the holiday weekend, so I can't wait.

Codes are as follows:
P0A80 - Replace Hybrid Pack.
P3011 - Cell Module 1 fault
P3022 - Cell Module 12 fault
(one would assume the hybrid pack, but it turns weird)
P020A - Cylinder 1 ignition timing issue
P0830 - Clutch Pedal Stuck
P0135 - O2 sensor error

The last three don't happen every time, but one of them is on every single time the code hits. And so far, I've deduced a 12V system issue rather than HV; it may be up in the inverter.

As I'm going down the road, I keep diagnostic up, and moments before the Christmas tree, my 12V pack drops from a healthy 14.4-14.6V to below 12V. The auxiliary battery is fine, and I've actually tested that side by pulling the brand new one out of my parents' 2005 and getting the same result.

My terminals are clean as can be. Every cell in my HV pack is actively healthy and balanced, whether by straight multimeter without a load or under a load. The HV battery ECU doesn't smell burnt, the wires aren't corroded or stripped or pulled out of the connectors, and testing between the negative terminal and ground on each cell shows no voltage leak either.

For the record, my inverter pump is still running fine, and my engine oil is filled.

Am I looking at a fusible link error, perhaps? I know there's the big one in the front and the small one right on the positive terminal in the back. I'm just lost at this point.