I would wait for the rug, until you have the shutters up and your furniture placed..it may take on a character of its own and you'll want to compliment. My first thought though was to coordinate with your kitchen and incorporate some black, with a black/beige stripped rug, which would be fun with the wallpaper and perhaps paint your chairs black, add the shutters and you could paint the window trim black and add a large black chandelier.

I read an interesting comment somewhere, where a lady invited a group of her friends over to lovingly point out all the problems they saw (through fresh eyes) with her home on preparation for sale. She said she was surprised at marks and damage that she had lived with for so long she no longer noticed them. We "owner built" a home previously, and when we came to sell 7 years later, we painted the garage and did those jobs that we had put off, and it became sad to finally see her at her best, at the end, when we could have been living in a completely finished home all that time. I read about a lady who decluttered her home, had it professionally cleaned (build clean, or bond clean) and had a professional styler do her home and she realised just how nice it could be and decided not to sell. :) ta

So if I want to include sustainable things in my house, where should I start?

A very simple layout keeping the floor space within the kitchen, the WIP takes up a lot of space with not much gain, The broom cupboard could be moved to the Laundry/entrance, narrow. If the wall has been bumped out to the eaves on the deck side giving an extra 300 depth to the kitchen you could make the island 2700 x 1200 and all drawers. The wall of narrow pantry will hold all pantry needs and more, no deep cupboards to dig into. cheers