Ali, I think you are overthinking this, let your back garden be more natural as a contrast to the structured effect of the tiles in the house. I don't think you need consistency, the pool changes the whole vibe of the area so design for the pool to create a welcoming oasis - think tropical island resort. Have you checked with your local Council if there are limits of hardscape you can have? Some Councils do limit this and that will include your roof, driveway, paths, patios, the pool, etc. As well if you want this much hardscape you will need to consider runoff and drainage, particularly to ensure your neighbours don't get swamped in heavy rain or you have areas that puddle and take days to dry out. Consider summer heat too, sitting outside and the radiated heat that comes off hard surfaces, white and light colours reflect heat while dark colours absorb it. As well too much hardscape does not absorb noise - your neighbours will hear all your conversations and noise from the pool will be amplified. If you want that pool area to be inviting, then it needs lush greenery around it to offset this and soften and cool. Carrara marble tiles around a pool look fabulous and would be a great contrast to your dark tiles indoors. The area outside your kitchen should be grassed and include gardens as space for your dogs, even a small tree or two for the environment and to create shade for the dogs. Artificial turf gets extremely hot and would certainly not provide a pleasant or suitable outdoor space for them. I think I would read up on the breed of dog you plan to get also and fully ascertain their needs to ensure you provide properly for them. If you are planning children down the track, they will want a nice safe, green area to play too.

depending on how you want to use the space my suggestions begin with a lightweight pergola with sections of shade cloth roof and walls to create privacy until some evergreen climbers could become established and replace the lawn with gravel or pavers and use the space for a couple of chairs and a table, narrow bench for a potting shed or water tanks or shallow storage shed for gardening equipment etc

If you want to know what grows in Adelaide take a trip to the botanic gardens. It's worthwhile. There are many styles of gardens within those grounds and as you walk around you will get ideas of things you like and things you don't. It's a climate similar to spain and italy. So generally all mediterrenean (sorry I can't spell this word never have) styled garden plants will do well. Citrus, roses, aromatic herbs (rosemary and lavenders grow like weeds there), olives, many types of bulbs etc, lots of hedging options. You have a great climate for growing fruiting plants that can feed your family. Consider this option. If you want your garden to look great you need to start with a specific style in mind. Look up Pinterest and you will find hundreds of pictures of various garden styles. Then make a list of all the plants that commonly feature in that style of garden you favour. From that pick your favourites. Make a map of your garden zones and write down how many hours of full sun each section gets. This will narrow your plant choices. Take note of the maximum height of anything you plant and choose according to that. Too many people plant something that looks nice as an immature plant and end up with a 10m monster in their yard at maturity. Your landscaper is right Adelaide is a clay pan, the soil needs to be improved a lot before you plant into it. Buying a premium garden soil mix is an easy way to do that but you will have to put a clay breaker underneath it too.

15 years is a long time so i would plan to suit the needs of your own family without worrying too much about future buyers and first thing i would like is a central pergola (covered with vines like kiwi fruit?) to help screen neighbouring houses and create a shaded outdoor seating area and separate the lawn from an enclosed yard for chooks and vege gardens with fruit trees and flowers planted in raised garden beds and/or big pots.. remove the central pathway (relocate the pavers across the back of the house to the line of the future subdividing fence and focus on as much lawn as possible for the kids' trampoline, sandpit and paddle pool shaded with umbrellas... consider one or both of the smaller sheds (painted to match the dark fence) for chooks and/or cubby or dog house and using raised garden beds built with railway sleepers, filled with soil mixed with compost enriched with chook poo are simple to build and move and can help overcome the problems with growing in sandy soil