I think this is a great analysis of how the idea of "free will" has been developed and discussed over the years.

But I also think that even your final usage of "free will" becomes unnecessary if we change our lens on justice and mercy from one of "responsibility" to one of "predictability".

If the growth hadn't been discovered on the man's neurocortex, then we might reasonably predict that his unlawful behavior would continue. But because we predict that the removal of the growth will prevent future transgressions, we are comfortable with letting him go free.

The correct way to place "blame" or "responsibility" after any undesired event is not to identify whichever agent was most conscious at the time, but instead, to identify whatever factor was, in retrospect, most predictive of the outcome.

And whatever corrective action we take should not be based on whether someone was "conscious" of their actions or not, but rather, based simply on whatever we predict will have the best chance of preventing the action in the future.

Ultimately, the lens of presumed consciousness or presumed free will is obsolete, and should be abandoned in favor of predictability, which is far more straightforward and transparent - and therefore also more fair and democratic.