If your scheme is properly run, your AGM will include a motion that allows the strata committee to make decisions on behalf of the Owners Corporation. Restrictions on that decision-making exist in the Act meaning they can make day-to-day decisions (like allowing pets or otherwise) but can’t pass by-laws or engage in legal actions above a certain cash limit, for instance.
In the case of employing a surveyor to assess the unit entitlements, I’d say that was perfectly legitimate.