You have cymbidium(s). Very easy to grow orchids in coastal southern California. The dead looking parts are called "back bulbs". They will never grow leaves or flowers again but they are certainly a viable and alive part of the plant. As long as they are connected to the rest of the plant they won't do anything. More on that in a minute.

As for fertilizers, at this time of year they don't need anything, just watered enough to keep them from drying out for too long, about every 10-14 days depending on rainfall. Nothing should be done to them while they are producing flowers. Actually the only thing you could do is use some thin bamboo stakes to tie up the flower spikes, they'll look much better when you do that.

Beginning in April as long as you are done enjoying the flowers, the plant should be divided into several plants. Each plant should have at least 3 to 4 solid bulbs, with at least one of them being new from the past growing season. This is called "dividing" into "divisions". Now back to those back bulbs - if you "disconnect" them from newer parts of the plants, preferably in sets of two or three connected to each other, they will sprout new growth from dormant growing "eyes" (sort of like a potato). It may take a year or two or three to bloom again based on your growing talents but it's a great way to increase your collection cheaply. The back bulbs are surrounded by dead leaf tissue but they are loaded with green life. Peel off the dead stuff as the plant will look much better and it will eliminate places for bugs to hide.

Anyway, divisions do not need to be limited to 3 or 4 bulbs, they can be a lot bigger obviously. Use black hard plastic pots just like the one pictured but give plants only enough growing room for two years.

There's a lot more to repotting and these links should help.

http://cymbidium.org/cymbidium.html
http://orquideas.com/growing/potting/cymbpot.html
http://www.orchardnursery.com/pdfs/orchids/repotcyms.pdf

Have fun!
Matt