IMO the lawyers and the tilers have it right and the Strata Manager has it wrong.
I’ve not seen acoustic underlay used in tiled kitchens, bathrooms, laundries, lavatories. They have typically been built that way for as long as I know. And any by-laws on acoustic requirements usually exempt them.
Kitchens are actually not considered wet areas under the BCA/NCC rules. So they don’t actually require waterproofing or floor wastes. AFAIK the choice of flooring in kitchens tends to be for practical reasons. In the building where I live all the kitchens have wood floors (so they are not much waterproof at all) but others that I own or have owned use tiles.
What type of flooring is there now?