I think, at best, we'll see a situation similar to the requirements that state schools have for enrollment. All 50 states "require" kids to be vaccinated.... but 48 states have religious exemptions.

At the end of the day, it's a lot less risk to HR to not piss off a couple of politically fringe employees over something that the vast majority of employees will do voluntarily anyway, without any coercing. Two unvaccinated employees out of hundreds probably won't cause a problematic COVID outbreak, but they could file a lawsuit.