This is a little scary.
So what's the best way to protect our domain names?
I'm assuming the domain needs to go to a domain parked page, for it to be under the monetisation rule?
Is a blank page with "this domain is for sale" a no go now?
Would a "Website under construction" page be better?
Should we be registering business names to go with our domains?
I can only speak from my personal experience. It seems currently the best option is to keep it parked on a monetisation page with links that are close and substantial to the domain name. Even if you have it monetised for 2 years and then decide to have a page "this domain is for sale" because you no longer want to monetise the domain and perhaps don't want to develop it any longer, you then become under the sole discretion of an auDA review officer of the outcome. If they had a bad day/week, they can simply say "sorry, your domain is no longer in policy" and delete it.
If you have a "Website under construction" page, you will also want to display any logo or trademarks you have to show that you are legit working on something.
Should we be registering business names to go with our domains?
If I registered a business name for every idea I had, I would not have any funds to try and build these ideas. What a vicious triangle.