If it’s anything like up in NSW, an audit of the building to current National Construction Code (NCC) is probably the first step to take…..although that now makes you fully aware of any and all liabilities. A previous 2019 revision incorporated changes, that depending on the construction, height and so forth of the building, could get extremely expensive and disruptive, if it applies.
Typically up here, a BCA consultant will project manage the defect side, but they generally have little idea on cost for budgetting purposes. An estimator or quantity surveyor is possibly worthwhile, but we found several years ago, a lot were uninterested in what was for them, a piddly project. Unless questions arise under your constitution, lawyers are probably at the end the process – winding up the company, etc.
I’d suggest having a sizeable war chest before embarking on anything if the building is a good age, several of the shareholders here have had to depart and I know of one building a few blocks away, where the owner topped himself.