Definately no overheads necessary, this glass section will look amazing, I've doe this in a kitchen, and it looks as though the tops been peeled back. It is amazing to have this size space, and tall cabinets next to the fridge will look fully integrated, my only thought is that while it may not need a walk in pantry, most people want one if it's do-able. To do both, I would offset another wall where your fridge is, by about 1500mm, keeping the fridge at the end, then as if the tall cabinets were there anyway, apply cabinet doors (panels to the wall with one of them actually concealing the entrance to a walk in, with full height open shelves. Tis way it's ample pantry storage, but also can accommodate a multitude of appliances and kitchenalia. When the pantry doors closed it will look like the design you currently have, with a nice surprise behind the wall. Best of both worlds. Taking the 1500mm off the width of this room will actually square up the rooms proportions anyway. So I'd do this.

Anything pre fabricated / flat pack will be the most cost effective. Going for a cheaper material like ply will save you some cost, but a lot of the cost is actually in the labour itself. Maybe combine some flat pack items with some custom made items so the fit out fits your space exactly and gives you that built in look. Good luck.

Hi I have a large bathroom with a closet for washer and dryer. I love it. Off my bedroom. But also have you thought about making study into bedroom with an en-suite and the laundry tucked in there behind doors. If your selling a bedroom downstairs for an older person its very attractive and nice to be separate from the others. Then the two bedrooms upstairs have there own bathroom. Also you are having toilet tucked under staircase for visitors. If you had heaps of space then yes have a separate laundry but it’s a waste of space when you haven’t. I have my laundry essentials in a cupboard under my bathroom vanity which is 1800 cm long and still have two 1m drawers next to cupboard.

I would go with 30cm depth as it allows more flexibility. I understand what you are saying about paperbacks and wasted space to the front not being a great look, but in my mind it is better to have that space at the front than to have larger books projecting beyond the front of the shelves which is what you would have with 20cm deep shelves. If it is a working library then the number and size of books may change over time and the 30cm depth allows for maximum flexibility. On a side note the 78cm long shelves need to be strong enough to support all of the weight of those books. The string shelving you are looking at is usually presented fairly sparsely (as in your photos). Nothing worse than sagging shelves.... Best of luck, Dr Retro of Dr Retro House Calls