Hi. I think there's little point in worrying about not having a three-chip camera for underwater work - the three chips give you better color saturation and a little better sharpness, advantages which are pretty much eliminated by photographing underwater, while a single chip camera gives you better low light performance, more important in my opinion.
Yeah, I grew up idolizing Cousteau (see my thread about the Calypso below) and went into documentary filming professionally, although most of it topside. I use Final Cut Pro and think it's kind of a pain - harder than it needs to be. That said, the editing software is a very small part of the puzzle. Most of my time is spent logging, planning, writing and conceptualizing, and I really haven't found a shortcut there! If your stuff is simple don't be afraid to use iMovie.
Nice Clip!