You also need to consider all the other consequences to a company owning property - no 50% CGT discount, income tax, dividends, succession, control etc etc.
http://www.austlii.edu.au/au/legis/nsw/consol_act/ltma1956173/s29.html
Actually it could be possible for one company controlled by wife and one controlled by husband to not be related and therefore get an exemption each - under some circumstances.
Yes that is correct. But check with your lawyer or tax agent as separate companies can be lumped together as one owner under certain circumstances. And there are different rules if the company is acting as trustee
If land values go up and exceed thresholds then you will pay land tax.
in QLD same with trusts. Watch out in QLD as beneficiaries can be liable if the trustee doesn't pay.