[J]ust a sketch proposal which demonstrates a promising avenue of research. A complete description would state what physical system in the brain is responsible for maintaining complex, "black box" quantum states [...]

What makes this avenue different from investigation of neuron configurations? New physical laws were never discovered after rejecting the old ones, saying that they couldn't possibly work. All discoveries of new physics happened after conducting research using the old paradigm and realising anomalies. I mean, if there is something strangely quantum going on in the brains, we will not miss it even if we use the conventional approach.

Or said differently, I still have no idea what light quantumness can bring into the question.

Do you fear that P-zombies will infect you with an epiphenomenal virus and cause you to lose your subjective experience?

I fear talking about things that aren't connected to observable facts. I fear that I might say a lot of grammatically correct sentences with no actual meaning.