For this site, and your own situation, the plan will work.
Regarding orientation. The living area will need external shade for the hot afternoon sun. This can be added when you have moved in, so you can then work out exactly where shading is required.
The bedrooms are on the correct side, they will be cooler in afternoon, main bedroom on the south, so that should be okay as well.
The problem I see, is that there will be no winter sun getting into your living areas from the north, for solar passive heating.
And regarding selling/renting, two separate living areas for a family, is beneficial. But this is your home, and you don't need that. One of the bedrooms could be a separate playroom if required.

You are lucky/ purchased well, that your back garden faces North (the most desirable direction) to allow for all day winter sun, and with minimal awnings, summer shade. You should try to optimise this with the bulk of the living area to the North opening up to a much more generous alfresco area. Pull the bedrooms/ bathrooms/laundry etc towards the “front“. For a custom build, I am not sure that your current plan makes best use of the block.

Have a good think about your life plans etc. How long are you realistically going to be in the house? Is it all about resale? Do you want to be a single living in a four bedroom house? Four bedrooms with only a single living area may be disproportionate and therefore off putting in itself. You can use one of the (many) spare bedrooms for a study, and a regular kitchen will have plenty of space for a single (even one who is a serious cook). If it really is for resale, best to discuss with local real estate agents, who will have a better handle on local requirements/ expectations vs forum users.

To me this plan looks like a volume builder plan, forced to fit the block- if you are doing that, you might as well have the savings of a volume builder. If you are going custom I think that you can get something better, that looks and feels custom to the block and to your situation

I like 90% , but theres a few bits I'd change .

The entry seems smallish , then contracts down into a narrower hall , which will be darker even during the day .

The master feels a bit small for what you are trying to achieve , the WIR seems a bit big , but due to the design , I can't think of rearranging that works , but I'd be tempted to 'step' the master out , similar to how the garage is .

Then you have another narrowish hallway running half the house , with 1 sliding door that isn't going to get closed much , unless its just for you , and you'll use your ensuite , and want to lock half the house off ?

Personally , I'd start again , have solid walls to hide the laundry , but have a couple of bedrooms , a study , and yes , a toilet , off the lounge , even if you have doors off alcoves rather than opening 'straight' off the lounge . Up to you though . . . . . . . . . . . . .

I’d flip the plan so living area faces North. I always suggest popping a basin into the toilet, it’s valuable to families. I think one living area will reduce your future rental and sale price. Can you make the study bigger so it could be dual purpose?

Thank you everyone for your replies.

@dreamer – I agree with what you’ve said. I planned on extending the Alfresco to go down the side of the house along the Living/Kitchen down the track which would add the required shading.

Now that I’ve read a few more replies maybe flipping the whole house orientation will work better, and I wear the costs of getting the crossover changed to make the most of the N/E orientation?

@HU-319610855 – I will be living in the house for the next 5+ years so I guess it’s long term. It’s the first house I will own/build so there is a million things running through my head. I was told to build with the future in mind, whether it be my own family or if I sell/rent, someone else’s, but I can see how that really complicates things as I need to think in the present!

I have gone with a custom builder more so for the fact that I know they are reputable and the workmanship will be top quality compared to some of the volume builders in my area, it wasn’t so much for a custom plan.

As I said above, would flipping the whole house orientation work better and optimise the light coming into the Alfresco/Family/Kitchen areas? Or would it be better to rework the plans as you said and have the majority of living towards the back of the house? One of my original designs did have the Alfresco running across the whole back of the house, but it was a 3 Bedroom design which I changed to 4 to suit the estate I'm building in.

@User - I thought the entry and hallways were standard sizing, 1.5m entrance and 1m for hallways? The house will have 2.7m ceilings throughout so that adds a bit more space. The reason for the divide between the family and bedrooms as I like to have the spaces separate to create more privacy for the bedrooms/bathroom/toilet. I wouldn’t want them visible from the living area.

An example of living at the rear, for your block orientation.
In the plan the theatre could be utilised as your study. And the kitchen could have bench height window to let the winter sun in.
Or kitchen turned to face rear of the block.
But the minor bedrooms will need external shade for summer sun.
More food for thought.

my suggestions to improve the arrangements of rooms for your own comfort as well as future sales or rental