You can use regular potting compost that you would use to plant other bulbs or perennials. You can add some extra grit and bulb food would be fine in the planting hole. The size of pot depends on how many bulbs you have and the size of display you want. The bulbs will bulk up in time so you can start with 3-5. I'd plant them quite close together in a pot, 3 would do in a 12" pot and plant about 6 inches deep. They would also do well in borders in your area. Water well and feed when they are in active growth.
I'm not sure what the timing of the flowers would be in CA as they are quite late to put up foliage in late spring over here.
They really are bulbs for all areas - from the smaller ones which are about 12-15 inches tall to some that grow 3-4 feet in height. I like the foliage as well, particularly the purple leaved forms. They produce interesting seed heads as well.
Here's a fabulous group from Wallington Hall. I've left the photo uncropped to give you a good idea of the scale.
