Breaking up the great solid block of colour a little bit helps to hide it. Next is the choice of what to plant. I'm leaning towards: ficus pumila, climbing fig, which can be pruned to hug the fence tightly, Himalyan blue bamboo, (but might sprout on other side of fence as well, so should have a 60cm deep root guard or be planted in pots) or waterhousia floribunda, weeping lilypilly, which can be pruned to a narrow, non-climbable hedge but 30cm might be about as narrow as possible. I'm just a bit scared the bamboo will move into the neighbours yard too...You also have to be careful to not plant anything with massive roots that could eventually crack your pool, and it has to be tough enough to cope with a bit of chlorine... Then, put in a dip line so you don't have to water such a narrow spot. Good luck, and let us know what you decide.

You need to choose a colour that pleases you but the inside wall of that alcove does lend itself to a feature. If you want more than just paint colour there are paintable wallpapers that add an embossed look to a wall and you paint over that. Check out Bunnings.

A house in our street is very similar to this, the owners have done a fabulous job celebrating the style of the house, the roof line and bessa blocks have been made a feature, they have decked the front and landscaped the gardens, it is dressed beautifully with 59/60s style pots lowish profile with three legs accopulco chairs out on the deck. I wish I could take a photo (but a bit creepy - going up and taking photos of some one else's front). They have put in new windows and doors. The front garden is large and they have views over the inlet here. It has gone from one of the worst houses to something pretty remarkable. The new Windows are black framed

I notice you have an aluminium screen door. Are the window frames aluminium as well? If so, you can re-paint them using a bonding substance called ESP. This is a link to Bunnings spray version but it also comes in a liquid you can wipe on and off: https://www.bunnings.com.au/flood-300g-esp-surface-prep-spray_p1560212 It's pretty easy once you get used to removing the screen and re-installing it (makes overpainting go away). It means that the paint won't chip off if someone knocks it which usually happens with aluminium and some other surfaces. Answering your questions, if you make the entrance lighter you may not need to make the walls either side lighter. I like dark - it is very dramatic and not as common. If you start with the entrance you can stand back and look at how it goes with the other walls. Also remember they don't all have to be the same. Variation in colour and texture adds interest, just make sure it doesn't look too busy and all the surfaces blend (not necessarily match). Your back wall is plain and straight, so regardless of the colour you end up choosing it will need to be augmented with something. You could try a large mirror on the blank space between windows. Something with a chunky frame in a contrasting colour and you will have a reflection of the greenery opposite. You could also try a reclaimed timber feature or something rusty or possibly a small timber pergola over the back door (similar colour to the window frames) that will give some depth. It's only paint, so try using patches with sample pots before you put too much effort into painting all the walls. Good luck.