I am not a fan of straight lines either. I like the red door.
Put up a trellis and planter along the garage wall. Paint the trellis white to match your trim. You can paint the planter box the same color as the house but I would put a finishing edge on the top of the planter and make the base of the planter out of laps to make it look a little more elegant.
Remove the brick and create a curved bed that goes from the corner of the house and curves around the semi circle area where you will put a small fountain or some other design element and run the bed past the corner and down to the edge of the driveway. You want it to be wide and not straight but more free form to soften the hard angles. Put matching planters at the corners of the house and find a tall thin plant to hide the downspouts or you can use a vine on a post. Where the edge of the brick planter is now you will put in large stepping stones to create a new walkway to the door. Put decorative yard lites along the path if it gets used at night. You also want that to be a natural looking path but not one that makes a bee line for the door. Around the new path in the beds select a theme and a color scheme. Soft red plants are inviting and should be at the beginning and end of the path to draw people in. I like dwarf acalypha as a ground cover. It has red chenille "flowers" that bloom most of the year and it is fairly drought tolerant. Around the fountain or centerpiece, make that circular area stand out. This is where i would use tiles or brick on it. In the planter by the garage wall and under the window in front of the house, you need a splash of color. yellow or pink flowers. Pastel pink alysssum will form soft mounds around the path. It is an annual but stays in bloom for a very long time. Either Mojave sage, bush sage, viburnum, spirea, sundrops (yellow flowers) shrubs can go in front of the window. Along the sidewalk you can put patches of color in groups of three or more or drifts of coreopsis, annual flowers, daylilies, don't forget color can come from foliage too so plants that have interesting foliage will give you long lasting color after the flowers are gone. The planter by the garage can be spilling with petunias, or layered with something taller against the trellis (keep the trellis away from the wall. Put the planter on wheels so it is easier to move to get to the wall.
When you make the garden bed prepare it well with lots of organic matter and mulch it well. Drip system will make watering easier.
Happy gardening in Hawaii. Gardens are where people grow.