gorgeous house and will be so much better with some suitable landscaping but, unless you think guests would be comfortable walking up and down the slope, i suggest that entry should be from the driveway with the extra parking area dug out of the slope at the right hand side of the driveway (as seen from the street) and have the gate house to the right of the garage with shade and screening trees and retaining walls stepped up the slope and screening shrubs between the parking area and front garden ...choice of materials and plants should have been suggested in your original landscape plans but an oval shaped lawn with formal symmetrical planting and a wide sunken lily pond in lawn feels like it would complement the house and cool the entry

the floor of the northern verandah downstairs can be any size to accommodate space for socializing but the upstairs balcony forming the roof over the verandah should be the minimum size to avoid shading the downstairs living areas when you want northern sunshine in cold weather (a simple market umbrella can provide extra outdoor shade in summer) ...you could even consider a Juliette/French style balcony upstairs so that you need only have fenced doors opening off the upstairs living room to enhance enjoyment of the views without stepping outside onto a balcony although as little as a 90cm deep balcony would allow space to stand outside without creating too much shade downstairs .....the issue of upstairs for elderly residents could potentially be overcome with a stairlift on easy access central stairs with wide entry and exit....a bigger downstairs guest room (bed 1) would be useful for now and later as a master suite and a future north facing pool house could incorporate a guest/pool bathroom...it could be useful to explore other ideas for a side entry but my suggested shorter front entry incorporating the stairwell keeps the void central and makes more direct access to every part of the house eg kitchen to front verandah and allows the side garden to be secure and private from uninvited guests and i'll make another plan with downstairs bedrooms reversed to see how that could work

this is a much bigger changes than just a wall and involves foundations, floor and roof as well as plans and Council Development application but the plans imply that you will be making the building smaller which is a very unusual choice but you will need to ask a builder for quotes

It's a shame that the door slides towards the shower because the first thing you see is the toilet. Could there be any other place for it? I love your inspiration photo but the two examples you have shown are not as inspiring. I would try a few more options before you set your layout in stone. I like the idea of the white vanity with the wooden top and try to find the black and white basin. Our best eye level storage is a recessed cabinet with a decorative mirror beside it. I can't understand this obsession with storing all the things you want to use behind the mirror you also want to use. Love that idea of tiling the kick-board to match the floor. I have also put mirror on the kick-board for the same effect. Wall hung cabinets definitely give the appearance of more space but do you out of some storage. I dislike the idea of a wall of glass at the shower unless you are a fastidious house wife because after a few years of being subjected to soap scum they can become cloudy and that can be permanent as I recently discovered in a rental property. In a tiny room the area can look larger if your tiles are laid on the diagonal. If you are forced to keep the same layout would you consider a piece of furniture for the vanity? Good luck. Remember the planning is half the fun.