I would try Omega fatty acids, such as those in Lipiderm or other fish oil products. Their coats should improve with daily use.

I also give my dogs yogurt in their food daily. Mostly to prevent gas, but it also helps their overall body odor. It sounds like your dogs need more water in their diet to dilute their urine. You might also compare the ingredients in their food to other brands. I found that Nutro keeps the odor down for both my dogs and the cats. I switched the cats (all 12) over from a cheap brand a couple of months ago and noticed the odor reduction right away. Since my dogs go outside, it was less obvious, but you might be able to see a difference since yours are inside. What food are you feeding?