I am not aware of any bushfire zone specific battery laws as all...

I am not aware of any bushfire zone specific battery laws as all electrical equipment must comply with Aust standard. That doesn't mean you can't use common sense like every farm does by keeping gas cylinders, diesel storage, flammables stored away from house . Just weigh it up with reality of ability of fire services access in case of a bushfire and unless you have a very high fuel load on your property then your battery probably won't exceed its general usage specs of temp range. Big difference between in storage temp specs and usage specs. Ask suppliers/ builder if there are any special installation requirements or suggestions as that is what they are paid for.

Having barrier , distance and airspace between any threat all help.

Bushfire danger - most is from ember attack so quality build with correct compliant materials and a bit of common sense by builder are important and long term will also help with insect and vermin attack. They are just risk mitigation not a guarantee that your house won't burn unfortunately.