Pittosporum tobira won't work. It likes shade to partial shade and will burn in full sun/reflected heat. It is also not considered desert-adapted due to their high water needs. Keep in mind the mature size of whatever you plant. A tree that has a mature width of 10 feet should be planted 5 feet away from your wall. Here are my sugggestions: Palo Blanco (Acacia williardiana) 20 feet tall x 10 feet wide, graceful branches with white trunk Mexican Bird of Paradise (Caesalpinia mexicana) 10 x 8, evergreen with yellow flowers nearly year round Texas Olive (Cordia boissieri) 10 x 10, evergreen with crisp white flowers spring to fall Hop Bush (Dodonaea viscosa) 10 x 8, evergreen, low litter Orange Bells (Tecoma hybrid) 8 x 5, tubular orange flowers Yellow Bells (Tecoma stans v stans) 8 x 5, tubular yellow flowers You can view these and more on line at the link below. Here is a link that might be useful: Landscape Plants for the Arizona Desert

Fruiting olive trees are messy! You can have them sprayed to prevent them setting fruit, but it has to be done at the right time. If you don't want the mess or to mess with the fruit, you'll need to have it sprayed or you will have MANY olives. Our dog used to eat them and ooooh did he have gas. Phew. My husband processed olives one year but they weren't worth the effort. I don't like olives but even people who did didn't like them. They were like strange tasting wood pulp. We didn't try pressing them for oil, and I bet you wouldn't either. ;-) I like the look of olive trees but not the mess and some people are allergic to the pollen.

how about a pic of the whole?

If you have any paving, Carrotwood and Podocarpus are both pavement lifters/busters. Podocarpus is one of my favorite trees, but they have massive root systems. Italian Cypress, but planted strategically to screen your neighbor's windows, rather than as a "Fort Cupressus" hedge. No bees on those. The Sunset Western Garden Book has a "What to Plant Near Swimming Pools" section. Every library in California usually has a copy if you don't want to buy one. The fruitless olive still blooms, it just does not produce fruit. The flowers may still attract bees.