I am by no means an underwater photo expert, but I did try to edit your photos in Photoshop (which I am pretty good at doing). I would approach your photos in one of two ways:
1. Either get a good flash or two strobes to properly illuminate your subjects, or
2. Do not adjust your white balance at depth and correct the color later in Photoshop.
1. A flash is obviously the best way to go. You will get better photos and minimize Photoshop processing later.
2. If you don't have a flash, I find that I get better results if I leave WB on auto and then correct the colors in Photoshop using the Mandake process. This actually works pretty good but comes in second to properly exposed photos with a flash. I find that if you 'correct' WB at depth then the Mandrake process doesn't work and it is much more difficult to correct the colors and contrast. But then again, some of the results above are pretty darn good using Photoshop methods other than the Mandrake process. I will have to explore some of the methods above. In PS CS2 you can automate the Mandrake process and save it as an "Action" to speed processing.