Well, I'd say a Bloodgood Japanese maple (the bright red kind), as they're almost the only ones that can stand direct sun, but they do have shallow roots. They do better in sandy soil vs clay as do most trees, and amendments just don't work for any tree, but if your soil isn't 100% heavy clay you may get away with one (plus they don't need as much acid as e.g. pines.

Gambel Oak (Quercus gambelli).

Most folks don't consider crape myrtles shade trees but they would definitely work in your situation. They grow robustly in SoCal, will produce a rounded canopy, won't exceed your size requirements, offer summer flowers, interesting bark effects, tolerant of urban pollution, drought (once established), a variety of soil conditions and heat. And they don't offer many of the drawbacks some of the more common shade trees pose - surface rooting, excessive debris, insect or disease problems, too large a size for a small suburban garden, or invasive or fire potential.

My sister has slowly been reducing the excessive number of liquidambars that were planted in her pretty tiny coastal OC townhome garden. Why the original owner thought 13 of these monsters was an appropriate planting for this minute garden is anybody's guess. It is impossible to plant anything else due to the root systems that have spread throughout the garden and they don't even get much in the way of fall color.

Mexican Plum comes to mind. Drought tolerant, clay-alkaline soil tolerant, typ. size range 15-25', medium/small leaves that have orange/yellow fall color, very good spring flowers, They do produce small fruit however, but not too messy. A hardy small tree.
An Eastern Red Cedar would fit all of your criteria but for the deciduous part.

What about a Jacaranda?

Here is a link that might be useful: Blue Jacaranda

Avoid hong kong orchid tree in windy situations.

Just remember that no tree ever STOPS growing. As trees near maturity, their growth slows down, but never stops completely. Your maximum height will need to be slightly flexible.
Good luck,
Mike