I personally think the cladding would look nice and be the easiest to maintain. We also live on the Gold Coast and have a brick house that has been rendered (not by us) and, to be honest, it is not particularly low maintenance (if you want it to stay looking good that is). It is prone to leaching which leaves ugly stains so regularly needs retouching with the paintbrush. It can also develop small cracks in the render due to temperature change and movement. However, the most worrying thing for us is with regards to termites. If you render over your brick on the lower half of your house, it is highly unlikely you will see the telltale "mud" they leave that indicates they are trying to gain access into your house (they climb up in between the render and the brickwork). I would be trying to keep the exposed bricks in preference to rendering over them, particularly if you have a garden bed up against the house anywhere.

The charring of wood as a method of preservation is nothing new and was known to European and Mediterranean builders as well as Asians. I have for years charred the bases of deck posts and such as a rot preventative. The practice is mentioned in John Fitchen's classic book Building Construction Before Mechanization. Some of the samples of this shown above are a bit crude. The most beautiful finishes of this type are rather labor intensive as some of the char can be brushed back off to some extent to reveal wood grain. The planter shown below has been coated on the interior with linseed oil, blackjack and turpentine and then set alight with a roofer's torch. The finish is cooked into the wood producing a carbonized insect and decay resistant surface. It gets filled with soil and so the char will be seen only at the edges.

For a cheaper, faster and possibly easier option, take a look at this for some inspiration. The lighter colour of the walls may reflect more light and be a stand out feature of your home. Click on the link and scroll to the image of the polished timber floor with the timber wall and ceiling. Polished timber floors with timber wall paneling

We want something that blends in, but because it's a zinc and colourbond shed home, I want to choose a colour that makes it look more like a house and less like a shed. I was looking at basalt but my husband would prefer a lighter colour for keeping the place cool in summer. My original choice was windspray but I'm a bit concerned it won't contrast enough with the zinc roof...but perhaps better than dune that might look too 'sheddy'...so hard to decide!