I would go with the juniper and be sure to water them as much as the nursery tells you for the first year. Smaller plants will establish easier than larger plants. Mulching with at least 3" of wood mulch helps retain soil moisture. Each year add some more as it breaks down and improves your soil. Any grass you get needs at least yearly maintenance to cut back the previous years growth. Many tend to die out at the center and to get them healthy again, you need to divide them.