Framed corrugated iron shutters left natural would be my preference, colour might be a bit 'try hard' and natural will sit in the environment more easily. Could even make barn doors with it if you prefer that look. The actual barn door fittings are the pricey bits I believe. Our cyclone was made of corrugated iron (by pro shelter builders) and it never ever budged (loud though) so a bit of coastal? wind won't worry it. You don't have much wind going by photo's, all trees seem to be growing upright so a regular build will be fine.

My piece of advice would be to make sure the plants you select can tolerate being around a pool. This will definitely be a 'splash zone' so any plant species that will get damaged or not cope with salty or chlorinated water. As an example, I have seen a beautiful row of Black Mondo Grass that suffered greatly from the pool water and died. Also be mindful of the size of plants you might be planting close to your pool. Plants with invasive roots or large palms can cause damage to the strucutre of your pool so their locations should be carefully considered. Good luck!

It looks like you have some great wall space. No matter which style or scheme you choose for you living room, you can't go wrong with built-in storage with doors - especially with kids. In our living spaces we have tried to build in storage with adjustable shelving that is big/deep enough to fit those large clear plastic containers with a lid and wheels that you can buy from Bunnings / K Mart. These containers are great for keeping like items together in such as toys, craft/art, sporting gear, blocks/lego, presents/cards/paper. You can bring out a container or two at a time to play and when done throw everything back in and close it behind a door. Once the kids outgrow what's in a container, you can donate/sell/bin the contents and re-use the container for the next thing. On your red wall, you could have a full floor to ceiling cupboard with tall cupboards at both ends for toys etc, tv on the wall in the lower middle, drawers/cupboard underneath for dvds, games and cupboards above the tv for less used items. You could also do something in the same same style/colour on the grey walls to the left including building in a workstation as part of it for craft or as the kids get older if you need more storage. We just have plain white flush doors with nice handles but there are so many great options for colours and styles - including red if you want to keep that wall red. Some Houzz inspiration:

depends on direction of sun and local climate...where is north and where is the house?..i'd buy a collection of big pots (plastic or steel garbage bins can look good) and add some rubble for drainage then deep mulch and sit your plants on top of the mulch and arrange the planters in groups to suit your furniture arrangements under the pergola and consider adding shade cloth screens around the whole pergola to shade hot sun, block wind, exclude bugs and make the space more comfortable for yourself and the plants...looks like a great house in an interesting location, congratulation