Ruthy, as far as planting in a pot, it would depend on what variety of lilac you purchased and what size of container you are choosing.

Plants that normally grow upwards, 8---10---12---16 feet would not survive long in a pot.
In a large container, maybe...as long as the roots have sufficient soil to take nourishment from.

If you have one of the lower growing varieties..it might survive well in a container---with the view of its roots still viable.

Overall though it is much better for your native grown lilac to be planted in the ground.
What they evidently don't like is to be overwatered and overfertilized. These California natives are grown for the type of weather they will normally put up with....and that means temperatures over 100 with low water needs.

Depending on the mature growth---outwards and upwards, you can plan on keeping your lilac in good health for 20 - 25 years as long as the deer don't get to them.

Ruthy - the one thing that might impact you for your lilacs is the summer heat. Most of the common varieties suffer during extended hot spells (the leaves crisp up), particularly when in pots... and I expect your climate is probably bone dry (air) during the summer. Otherwise, I have been growing lilacs in pots for about a dozen years and they will dwarf naturally (my containers are 20"). If you keep them pruned to balance with the roots, then they will do okay - again provided they can adapt to the heat. In winter, they should be fine. I have colder tolerant ones ("Miss Kim" and "James McFarlane") and they have taken single digits without a problem.