Ask for advice on the California forum - conditions and appropriate plant selection are a bit too different up here in the PNW for you to get many good suggestions.

And be prepared to modify your requirements a bit :-) A tree meeting ALL your requirements is going to be very hard to find - ex: trees with interesting color generally will be deciduous, so leaves will fall in autumn. Even broadleafed evergreens like magnolias or arbutus (both possible choices) will experience leaf drop of older foliage.

Danville is very hot and dry, not at all like the PNW.

Any tree will drop leaves.