I'm sorry to tell you that your blue star juniper will more than fill that space on its own - the lavender won't take up much room widthways, but the Delosperma (ice plant) would also fill up most of area, so really, there isn't room for anything else. I suggest you remove the blue star juniper altogether - it will spread all over the plant behind it where its planted now and is altogether too large for such a small area. When choosing plants, checking their eventual spread as well as height prior to planting is important.
Blue spruce sedum will spread up to 12 inches all round; rosemary will be a large shrub, 6 x 6 feet, so you can see that area is way too small for all these plants. Hopefully, you can find somewhere else for most of them.
Rock plants are usually much, much smaller subjects - Armeria maritima, for example, is an evergreen perennial with grass like foliage and bright pink flowers in spring, but it doesn't get much bigger than 4-6 inches wide. Others, like Euphorbia myrsinites, get about 6 inches tall with a spread of around 10 inches, whereas Iberis sempervirens can spread up to 2 feet - these three are evergreen. Some guidance can be found at Rock gardens: plants.
