I was also going to suggest that you drive around your area looking at any new builds, who's building them and what Architect/Design firm has been involved. You could introduce yourself to any builders that you felt you might be interested in working with, call the Architect etc to discuss. If you can find locals to do the Job that's a plus, if there are any problems they are on the spot to sort. One of our Houzzers had a very bad experience where the Structural Engineer changed something without consulting anyone which ended up causing a major problem and expensive to boot. As annb has rightly pointed out you don't need to employ the Architect for the complete job as this will be more expensive, if your builder is good at his job he will manage everything with your input. Architects plans can be more detailed/complicated and sometimes there may be the need for the builder to check back with him/her. Big plus is that you are building where you live and are able to keep tabs on how things are going, very exciting time for you and your family

siriuskey, Yes, the courtyard is open to the sky (no roof over it), I assume this is what you mean by double story. Ref. below photos, I would love to get this look, especially the first and last photo, where you can see family living space from the first floor. I can't achieve this in my plan as it eats a lot of floor space upstairs. The referred plan (photos) has a very big void combining staircase, hallway and dining area. I know it is not easy with cooling and heating when you have such a big void. So, I explored a few ideas (with my limited knowledge on this topic) before achieving the current floorplan. I have also thought about, in my current plan, extending the void on the staircase to the dining area (it is more like L shape) but i wasn't sure if that makes any difference. keen to hear your thoughts.

From a "passive solar design" point of view, everything is right. Rectangular home facing north/south. With north facing living rooms, rarely used rooms to the west. But one other thing to consider, plumbing. Locating it close together will lower building costs, & the wastage of water, waiting for hot water. So I'd consider swapping bedroom 4 for the western wet areas. Behind the kitchen is have the laundry, then bathroom, then linen, the bedroom furthest to the west. I'm not mad about western bedrooms, especially in hot climates. But in this case it sounds like it would be used sparingly. Plus if make sure there was no western window, just a northern one. Insulating the western wall well, & using a radiant barrier (reflective insulation). The approach will also significantly shorten the length of the western hallway. Greatly increasing the size of bedroom 4. Talking room sizes, & room numbers, from a sustainability point of view, I think the home is too large for what is likely to be a two person home for much of the time. The embodied energy (emissions created) from a new build home is huge, averaging 15 years of operational energy. I'd be looking to reduce the house size, by using multipurpose rooms. The occasional kids housed in the study, or the media room. This can work out great with clever design (like incorporating murphy beds). How will the media room be used? Will noise be an issue. Will you be happy to have it so close to the master bed? The building orientation/shape will be great for solar PV, with a large roof area facing north. I'd I was building nowadays, is be aiming for an all-electric home. Ditching gas - of its even available where you are - in favour of efficient electric appliances. Reverse cycle AC for heating (if it's required), supplemented by fans for cooling, hot water heat pump (extremely efficient), induction cooktop (sensitive, fast acting, easy to clean). All powered by solar PV. If it's an option, I'd look at 3 phase power, which will let you install a larger PV system. It will also allow you install a fast charger for EV, likely to be your next car purchase, or soon after.

@ddarroch - you suggest rotating the home so it faces a compass point. Which compass point would you recommend? I'm leaning towards north facing but would appreciate your thoughts on this. Based on what I have read online, and the fact that we live north of Brisbane in a rural/residential area, I am trying to achieve a house orientation that excludes direct sunlight and minimises radiant heat at all times of the year and maximising access to cooling breezes. I'm just not sure how to achieve this on the block we are now building on as I keep getting conflicting feedback.