The city union disagrees rather strongly with that :) In particular, the city’s contract with these workers does not require them to be vaccinated. If your boss sprung a new rule on you and then fired you for not following it, you would be pretty upset too. Especially if it required you to take actions that you thought were potentially risky to your own personal health and safety. I’ll let you read the ruling yourself though, since it was more nuanced than that and I am tired of transcribing from a scan of a printout of a digital document.
Having multiple separate orders that result in an unconstitutional outcome is not really different from having a single unconstitutional order. I don’t know why you keep bringing that up; it’s not very interesting.
Also, awarding back pay is super common in wrongful–termination suits. Any time the harm resulting from a tort is monetary, it is quite ordinary to redress that harm through monetary means. In fact, in most cases it’s one of the easiest forms of harm to redress. The court cannot undo the harm to someone’s reputation nearly as easily, for example.