Hi there - a few things stand out to me... yes keep bedroom sizes no less than 3000mm wide, offset the door to the laundry so you can't see the toilet from the front door - yuk! Minimise/simplify number of piers by turning front porch 90º. Keep the footprint as simple as possible. With oklouise's plan, which i think makes more sense, cut 300mm into each of the bedrooms and push out towards the left into the deck. Much better use of space. If west is to the left put a whole wall of cupboards along in bed 1 and get rid of the others, and add door out to deck on the (new) north wall. Do you really need a bath? Living in country they are wasteful of water even if it goes back onto your land. Alternatively have a combined shower/bath? Babies and toddlers wash quite well in the laundry tub then learn to shower with you or on their own quite happily. I'd make the shower a big bigger (and the cupboard on the hall side) and get rid of the bath. Make sure you have excellent insulation in walls, ceiling and under floor. Consider hebel panels as flooring (also, the reinforced ones span great distances) and walls for both fire safety and insulation value. If possible look for ramp potential in case of disability and also for getting furniture into house. If you're in a fire zone make sure all windows and doors comply with your zone rating. And if you are building high up on piers make the external cladding is something that never needs painting and is minimal maintenance.

littleniffer, that downstairs rumpus has access to ZERO windows. It will be dark & cave-like. I doubt it would be legal as I think all habitable rooms must have access to external ventilation & light (I may be wrong). Wouldn't be pleasant in any case. Although I don't like internal wetrooms without windows, I'd probably prefer that than a cave-like rumpus. If you've got enough land I'd suggest stretching the build or as far as possible along the east-west axis, increasing the length of the north & south facing walls, while decreasing the east & west facing walls. This should reduce the excavation required. Though the main benefit (along with better passive solar design) would be if you can get away with downstairs being only one room deep, then all rooms will have windows. I'd have an open staircase, not closed, so light can pass between each tread. Unusually, I'd try to locate the stairs on the north side of the house, & have the flights facing north & south, to increase light to the downstairs area.

I think if you were willing to lose the back covered porch next to the bath, you could extend the bathroom and just have a walk way to those stairs. What concerns me about using the meals area, however, is how you would access the stairs to the cellar. That is something you need to figure out. Walk around your house, consider the options and walk the spaces to see how they might work for you. If you have trouble visualising it, you may need to measure it all out and draw up a plan of the space yourself. measure your furniture and cut little shapes to scale and move them around the plan to see how they fit. The bigger your plan, the easier it will be to figure it out. You need to think, too, about how you live in the spaces at the moment and what works for you as well as what doesn't. We lived with our kitchen for three years before settling on a layout we both agreed would work for us. We totally renovated our downstairs, changing the layout of the spaces and putting up walls to define spaces in what had basically been a walled in under house area. We discussed, changed and drew out the layout about 4 times over about 18 months, until we got the one that just felt right. We have lived with it for 18 months now and it is working very well, enhancing the way we live just as we wanted it to. My point is, don't rush to a decision. This is going to cost you a lot of money and you are going to have to live with the result for a number of years. Think it through carefully and figure out what will work for you and your family.

In the case of front to NE and not wanting to add anything to the footprint, the plan you have at the top of this conversation should be great. It opens the whole one side to social rooms with the study/bed 3 as part of that but close enough to the bathroom as a guest room or other purposes too. I would go without a bath but pop laundry trough and WM instead... very convenient having it in the bathroom. Avoid the dead corners if you can in pantry and robes. and add robes to the bed 3 too. Maximize the rooms: the walk up the steps does not need to be wider than a meter and if you can make sure the view is not straight into bathroom from sitting area. Much nicer. Cheers Go well! Margot