Your mockup scheme is similar to our master bathroom we just completed - photo below. I know you mentioned storage being a concern - our mirrored cabinet has offered an amazing amount of storage in a very small space and also helps bounce light around. I was worried about black taps etc too so we kept chrome fixtures but added in a matte black candle and black potted orchid to create a similar effect which we can change out later on. Our floor tiles are dark but because they are semi-polished they actually bounce around a lot of light and don't make the room feel dark if that is a concern. We also have a huge fiddle leaf fig in the corner (not pictured) which adds a really nice feel to the space - a plant like that could help bring in the outside greenery in your bathroom. Instead of the storage tower you have to the left of the vanity could you do say some floating wood shelving, possibly with baskets added for more hidden storage? You could also bring in the 60s theme with what you displayed on there eg. photos as you mentioned? In regards to the window - a previous house we lived in had a window at about shoulder height in the shower - as well as letting in heaps of light it was amazing for storing toiletries etc!

Is the door solid core? If not, a solid door would help somewhat, but would have to check the track can withstand extra weight. We have a couple of very heavy solid hardwood doors in steel frames which run on steel tracks. The bignheavy doors do dampen noise but certainly doesn't eliminate it entirely. Heavy drapery, rugs, soft furnishings, tapestries and large textile wall hangings will help to absorb sound from within the room, but still won't entirely eliminate it. If you don't already have carpet runners or rugs in your kitchen, adding some will also will help. Same goes for any other rooms which adjoin the music room/library. I knew a couple who soundproofed their small music room when they built their house. Their son played drums. As I recall, they used a special acoustic plasterboard for the walls, and the floor was carpeted. I think it helped considerably. there are also acoustic panels/tiles that can be installed on the ceiling, but this may be more trouble than it's worth. I'm not sure but the installation might be something like a suspended ceiling.

this house is such a great example of it's era it would be a shame to change it too much and the dark framed original windows and doors (with horizontal divisions not colonial panes) stained or painted a similar dark colour (including black) would be excellent but only over the original dark trim and others will make better suggestions for colour schemes but if you decide to add the entertaining areas, carport and covered walkways, dark posts, fascias, decking and pathways could make a a nice contrast with the blond bricks..DIY can be a great cost saver but having recently almost completed a similar renovation and about to start on another (we're also a retired couple) i would strongly recommend that you invest in a builder to take care of the overall construction and save money with careful planning (to avoid last minute changes) demolition (NB there's probably asbestos to consider) we saved by sourcing all our own taps, tiles, sinks, doorknobs, light fittings and happily recycled many of the existing fixtures and fittings (including sections of plaster cornices and etc and you could try painting, DIY flatpac kitchen and wardrobes, and consider prioritising the work based on your personal daily comfort eg although i suggested the old sunroom is worth renovating as long as it's safe and weatherproof the upstairs doesn't really need major changes and you could concentrate on the biggest project first OR start small and work up but it's always preferable to plan the whole property to avoid duplication and have a builder quote for the whole renovation and then you can stagger costs (and stagger out of bed each day) doing work in stages...In the meantime i'm assuming that your plans are from a real estate add so your very first project would be to make a very accurate plan of what you already own so measure every wall, thickness of walls, position of windows and doors, width of stairs etc ..even a few cms can make a huge difference in your options (eg the floor of the "study nancave" is probably lower than the living room and not waterproofed so do you want/need it enough to raise the floor, step down, enter under the stairs through a secret tunnel, come in through the old garage or leave it for the the boys??) obviously i can write ad nauseum but you will need proper plans for the external structures so it would be worth investing in professional drawings for the internal work as well your pre-planning will save time for the professionals (and your money) if you're reasonably confident about what will fit the spaces and i would be happy to revise the plans if you want to message me directly with the accurate measurements

Lovely colours ect. But my question is why is we read article after article on kitchen designs with advice from designers stating never to put a dishwasher in a corner as it is not practical. Articles always state that it should never block access to another cupboard and if possible access from both sides. First thing I noticed in the picture was the dishwasher. As an owner I would not be happy with this design by a professional. But this is just my opinion