Yes, I've been wanting to know their sun signs too. I did an analysis of my class when I went to business school, and sure enough, there was a large preponderance of Capricorns - something like 14% if I remember rightly. Quite a high percentage of Librans, too - oddly enough, it's often the sign of the manager.
Anyway, I find astrology a very useful and accurate tool for quick-and-dirty personality typing, even if only for practical purposes like buying birthday presents that the people concerned are likely to really enjoy. And yes, sun signs alone aren't as accurate as the full picture, but I still find them the easiest to recognise.
So... I could easily see Howard as an earth sign - that is, Capricorn, Virgo or Taurus - but he does have quite watery-looking eyes, so I can see your Pisces point. James also has that watery look, even more so than Howard, and what an emotional guy he is - I could easily see him being a Cancerian. Yasmina's very cool and controlled, so could be another Capricorn, or maybe her cool comes from an air sign - Aquarius, most likely. Ben seemed kind of Aries / Sagittarius. Lorraine I could see as either air or water: Libra, maybe, or Cancer? Debra is a tricky one - I'm inclined to think she's a fire sign, but not sure which one to bet on. Like Ben, I could see her as Aries or Sagittarius, less likely to be Leo.
I shall continue to muse on this question, but in the meantime, if anyone has any birth dates for any of the candidates, they will be much appreciated!