That was a sweet presentation. The whitetip video portion was especially nice. I saw whitetips while I was in Costa Rica (not Cocos, unfortunately), but only a few at a time and usually lounging around as I did strickly daytime dives. The video of them hunting in large schools was incredible and, quite frankly, a little un-nerving. It would take me a while to get used to being around that many sharks at once and not worry about them enough to shoot video.
The photos of the hammerheads were great too. I've not seen one yet while diving. Next to seeing a whale shark or dolphin while diving, I think they would be my next top choice. Looks like you had a great trip. Isn't CR great?