Jesjes my advice is that you don't overthink it or try too hard. You just need to get the balance right which you can do without spending a lot of money. I have a lot of mirrors, all sorts and consoles and lamps, I love lamps. Pity you don't have a power point there or I'd suggest a round lamp base, as large as symmetry allows with a great circular shade near the end of the console, it would take the eye away from the mirror and create a more finished area. The same can be achieved with a largish round matte vase in any colour/pattern you like with some black sprayed twigs or something. You might find vases I'm talking about in an op shop, I have a couple of unusual ones from the 70's and I get a lot of favourable comments. Then you could reframe the horse, I think a fine black frame would be lovely and it could still go on the console, add a horseshoe and the consoles done! You don't really need to add a horseshoe but it would start a lot of conversations lol. The current plant needs to be moved. Good hunting, have fun!

It’s a bit difficult to tell from the photos, but it seems the paving is in good condition? Maybe a pressure clean? Against the colourbond fence, maybe establish some shrubs that will eventually get tall enough to screen the next door house, and soften the fence? The back deck and stairs - does that flow from your living room. Maybe if budget allows, extending that with a nice deck with wide stairs could increase the connection between inside and outside, while reducing the overall expanse of paving. There is a sold wall next to the yard where the hills hoist used to be. Which room is this? It would be nicer if that room had windows overlooking the yard, or doors to link it to backyard - but this could depend on the function of the room. If not viable, needs something to soften the blank wall. Turfing the part of the yard where the hills hoist used to be, may make a big difference.

You could keep a picture there and add a second large portrait shape piece to left, or have a large wide piece to left, replacing current pic with a tall lamp or other item on dresser in corner to balance. Or just a slightly large where is leaving rest of wall clear noting it looks a narrow walkway

Where are you building, in order to understand climate, and which way is north on the plans, to address light and energy efficiency? The downstairs powder room shows a shower so it appears to be a bathroom however what purpose does it serve as there is no downstairs bedroom? I can't find the fourth bedroom either. There are things that appear inconsistent, for example a way oversize kitchen complex befitting huge parties but no entry, nowhere for guests to take off coats etc, the luxury of not only two WIRs but a "make up" room also for the master suite, but the ensuite has only a single basin vanity and the wc is not separate. What is the pupose of the nook? It doesn't look large enough for more than one person at a time so is it fulfilling a purpose for you? Why are there so many AC ducts upstairs and none downstairs? What is "organic" about it, apart from sales pitch? It looks overly generous in some aspects while impractical in others. There is something to be said in these times for trying to build 'right size' rather than continuing to build houses which are the largest in the world, but even if that doesn't concern you, why build a large house which reduces or omits valuable features which would be expected in a house that size?