“There is a big difference between requiring vaccinations for new hires and changing the rules in the middle of the game for existing employees.”
Although I agree with this as an ethical or “best-practice” rule, for better or worse most employment arrangements are legally “at will” so the employer can change the rules governing wages, hours, and working conditions subject only to restrictions codified in state or federal law or union contracts. Twice during my career I was subject to mandatory unpaid furloughs, which were equivalent to a salary cut, because of declining revenue. There was no legal recourse; I could either accept the furlough or quit.
“The second is a blatant Nuremberg Code violation, attempting to use duress to influence medical treatment.”
https://fullfact.org/health/nuremberg-code-covid/
Your link dances around the topic.
At the end of the day I expect there will be Nuremberg 2.0 and the defense attorneys will use all those arguments—and then watch their clients shot by firing squads.
The victims of these vaccines will not be impressed by the “legal” arguments.