Even though that is a fairly small space you could put some decorative trellises just in front of the fence with some ever flowering vines on them. Install a paver patio between them and the windows you hope to transform into doors.. You could also have the wisteria trained onto a pergola that would create a little shade for the patio as well. Some beautiful potted specimens/flowers and a couple of attractive outdoor chairs and you would have created a beautiful "picture" to act as a focus to the room. Additionally you have extra space for entertaining. Obviously the reason the previous owner obscured the window was because there wasn't much to look at. By creating a "view," you change the dynamic of the room as well as getting the light you want. Actual light will brighten the room like no change of floor would.

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!

That will look beautiful. You asked if it's too much work...which begs the question, WHO will be doing the work? Will you hire a builder, subcontract out the parts, or do the work yourself? That will help answer the question, I think. If you have a firm price contract, the budget for it, and a timeframe you can live with, then sure, why not?

If you don’t like the fence then remove it. It doesn’t really fit in with the era of the house. Returning a window to that blank wall would improve the look of the house. It currently looks odd and unfriendly. Windows improve your street presence. Choose windows in keeping with the rest of the house. Also think about orientation. If the front is facing west you’ll get harsh western light in summer heating up that room unless you have vertical shading. It might be why they bricked it up in the first place. Which brings me to the awning to the right of the house. It is what makes that window look odd. It would greatly improve the look of the house if it was removed, but if your house faces west you might regret it. Really think hard before rendering. Bricks are virtually maintenance free. Render will require ongoing maintenance. And there is the potential to look like you’re trying to turn the house into something it’s not rather than embracing it. As trends go, brick is back and render is on the way out. Not that you should always follow trends. Your money might be better spent on landscaping and other things that will improve the amenity. Congratulations on the new house. It’s very exciting.