guess they weren't playing with these policies
Most of these employees are unionized workers, governed by the language of the collective agreement. Employers have to use the language of the collective agreement to justify the termination, and that will be hard to do, unionized employees are protected by "just cause" clauses.
These terminations will be different from nurses being terminated because hospital nurses are also unionized but their collective agreement includes vaccinations, City employees does not. Tricky situation for the City, it would have been easier for them to put them on leave without pay indefinite, like the federal public service is doing.