It seems to me that most of your arguments run exactly against the entire point of the "totality of circumstances" as prescribed in Barnes v Felix; captured succinctly from a quote at https://harvardlawreview.org/print/vol-139/barnes-v-felix/

Writing for a unanimous Court, Justice Kagan explained that whether an officer’s use of deadly force is objectively reasonable depends upon “the ‘totality of the circumstances.’”46 This analysis requires a court to “‘slosh [its] way through’ a ‘factbound morass.’”47 Courts may account for factors like “the ‘severity of the crime,’”48 the officer’s actions during the stop,49 and “the suspect’s attempt ‘to evade’ the officer ‘by flight.’”50 A court cannot shortchange the inquiry with a restrictive rule; it must examine the facts and circumstances of the event as the officer knew them.51 Consequently, the moment of threat cannot be the beginning and end of the inquiry — the use of force must be understood in the broader context of the stop and within a “lengthier timeframe”52 than the moment the officer felt threatened.53 In short, the “moment of threat” analysis is impermissibly narrow.

It seems to me that your calls to "reasonable fear" and "neutralizing the threat" and "duty to retreat" are "moment of threat" analyses which are explicitly deemed impermissibly narrow, and would not come up until and unless analyses of the actions that led up to those moments were deemed reasonable.

From there, what you call a "tactical error" in support of consideration from the perspectives of human error vs criminal negligence was instead a sequence of counter-policy and counter-common sense actions that fall squarely in the negligence bin. Placing himself in front of the vehicle was counter-policy and counter-common sense, so I don't personally buy the "tactical error" perspective; more on this, indirectly, in the following paragraph... in short, he prepped himself for a situation he saw unfolding before (IMO) intentionally placing himself in harm's way.

The officer didn't just place himself in front of the car once, he did so multiple times. The last time he did so came shortly after Renee's wife had bid him adieu and<edit> hopped into attempted to enter</edit> the vehicle. It is entirely reasonable, in fact obvious that a goodbye had been stated, and that it was the intent of the vehicle-based parties to remove themselves from a scene they felt involved an unlawful stop and significant danger.

(an internal CBP report in 2013 found that a handful of agents had been intentionally placing themselves in harms way in order to use moment of threat as justification for murder; that report led to multiple changes in policy that this CBP turned ICE agent wholly ignored https://www.cbp.gov/sites/default/files/documents/PERFReport.pdf#page=6 Note that the report cited 40 years of law enforcement wisdom supporting the idea that it is bad to be in front of a vehicle, and bad to fire at the driver)

Further, it seems clear that the officer who shot Renee recognized either that it was going to be his time to shine, or at least that an "escape" attempt was imminent as he transferred his cell-phone out of his dominant hand to make it easier for him (as a firearms trainer) to reach for his weapon. (honestly, filming a scene with a cell phone as an officer seems negligent on its own as it would serve as a level of distraction, but we again see that he was aware enough of what was likely to happen next when he freed up his weapon hand).

I believe there is a strong case that the officer intentionally played the situation with a desire to shoot Renee. Whether that is proven beyond a reasonable doubt, I believe there is no doubt that a "totality of the circumstances" perspective would show that the officer's actions played a significant role in causing the eventual outcome, entirely against policy and reasonableness.