This is what you start with:
1. Remove sprocket from AVCS mechanism. This uses a T30 tamper-resistant Torx Plus bit.
2. Gently pry the sealing flange away from the casing.
3. Now you can disassemble the mechanism by popping out the middle section. There are six spring-loaded seals that will come apart, but they are easy to reinstall.
The piece on the right is what bolts to the camshaft. Notice how it has a spring loaded plunger that locks into the sprocket carrier? When I pressed it a few times look what came out (no, not the nickel
Hopefully this means I was right and the sprocket was getting stuck in the position where the plunger engages (0* would make sense). This would also corroborate with the cold start/reset ECU evidence where the high oil pressure of a cold start was able to unlock the sprocket, but the next time it went to zero, it wouldn't recover.