I'd plan to have a rhythm of heights. Then large clumps of plants, also with a repeating rhythm of colors. Map out your space and then start filling in with the mature heights and widths of your plants. Move things around until you're happy.

Great rocks! How we used them in our yard is to put a rock with a shrubby plant and a coarse textured plant like an aloe, agave, or cactus in randomly spaced groups.

Love your plant list but that water loving Canna seems out of place with your other low water use plants. Usually plants that come from similar environments take the same kind of care and look better together IMO.

Boxes the approximate mature size of your plants can easily be moved around to get a pleasing look, and also after the fact

transplanting when something looks off which I've done way to many times!

Instead of a straight row of plants along the fence, you need some depth...so some areas of the border are deeper than others...curves with a natural line of planting beds.

So some areas a few feet deep with thicker taller foundation plants behind the lower wispier ones. And some areas only a foot or two deep next to the fence.

The rocks should also be grouped together in different areas.

If you put up a picture of your sister's chartreuse shrub we can probably give you a name. Then you can get more so you'll have multiples as recommended above.

Some visual idea