A thick concrete wall can keep your house cool. Steel will make your house hot unless you insulated the walls well. Insulated walls don't work very well in a flood zone. When they get wet, you need to tear them apart. You will need concrete for the foundation most likely unless you are driving steel pylons. There is probably a combination of the two that will suit your needs best. It would be helpful to know what you want to achieve by using steel. There are advantages to both. Steel floors can be cantilevered further. It is easier to make bigger window openings. Floor and roof spans can be lighter and quicker to build with steel, but the roof will get hotter and therefore need good insulation and need to be well ventilated. These are just general assumptions of certain building practices so that you know what to ask people where you live. The practices and resources vary from place to place and building something for a specific purpose can change the benefits of one material or the other. My best guess is that you will probably want to use both.

I think a comfortable distance between the island and the counter is around 42". It seems that you have only 30" between your cook top and the counter. I might be a little too tight. The wall between the entrance and the kitchen could be 4' long instead of 6', you would then be able to move the island a foot which would give you more room between the cook top and the island. Could you switch the location of the toilet and vanity in your dad's bathroom so your enter facing a vanity instead of a toilet which is a lot nicer.

Dear Crazyjunglite, please let me add some ideas for your space. I beleive that a nice combination of two curtains like the one with the blue and peach double curtains in the picture, will give you an eclectic feeling that matches to your painting. The combination of colors that I suggest is this blue with brown flares and the cream-peach taffetas, and the soft cream sheer behind. It will join all the rest beautiful items suggested by now: https://www.etsy.com/listing/163787105/blue-curtain-polyester-fabric-122-inches?ref=shop_home_active https://www.etsy.com/listing/163785041/light-yellow-beige-curtain-polyester?ref=related-6 https://www.etsy.com/listing/167660815/35-discount-for-one-pair-of-two-beige?ref=listing-shop-header-1 https://www.etsy.com/listing/167363693/ecru-sheer-curtains-fabric-118-inches?ref=shop_home_active

How do you decorate your place, what kind of style, colors, and feelings? That will greatly influence the type of door you might want. Also, think of your budget, and whether you want to install it yourself or hire a professional (you don't need to tell us, just keep that in mind). Then look around Houzz, in the products page, they have lots of interior sliding doors and hinged ones, from elegant frosted glass in a dark wood frame, to rustic reclaimed wood planks. You may not want to purchase that exact model, but it might give you a better idea of what would fulfill your airflow needs without sacrificing style.