Check to see if anyone is having success with fruiting Pawpaw (Asimina triloba) in your area [I don't know if it can take Santa Ana winds.]. That is the only Annonaceae family fruit which I like even better than cherimoya.
I have heard very good things about Annona vepretorum, from southern Brazil, which might do well in your area. Southern Brazil also has several very tasty, but very seedy, Rollinia species, which also might do well in your area.
Annona crassiflora, from the dryish central Brazilian plateau, is also amazingly delicious, and possibly tough enough for southern California. It has a serious lack of adaptability to soils outside of its native area--- may need extreme acidity? Mycorrhizae?