Yes, they can be beautiful in So Cal, but they are falling victim to polyphagous shot hole borer.

Yes, they reliably produce fall-winter color in SoCal. Neighbor's tree still has about a quarter of its leaves.

It's my understanding you need to chose your liquidamber in fall for its color. Some stay green. We have several blocks of them and some turn and some do not.

You can purchase cultivars of liquidambar that will that will more reliably color to your preferences. For some examples, 'Palo Alto' turns various shades of red, 'Burgundy' a deeper purple-red and 'Emerald Sentinel leans towards the oranges and yellows.