I think in your shoes I would be saying to all concerned that either they bring the scheme into line with the law or you will be applying to NCAT for the appointment of a strata manager who will take over the running of the scheme until such times as the block is fully compliant.
However, this is one of those “be careful what you wish for” options because a competent statutory manager will start issuing notices to comply and special levies based on what the building needs rather than what the owners want.
Why would you do that? Because when the other owners move on, leaving their unauthorised alterations the rest of you will be left with responsibility for their repair and maintenance.
This would be a good time for the other owners to sit down and start talking sense while they still have the opportunity. Otherwise, you can always unleash the hounds – and the statutory strata manager only needs to go by the book; they don’t need to listen to anyone.
By the way, it doesn’t matter when the owners had the flooring installed – if it’s too noisy, it’s too noisy and they have to remedy that.