K.A.
I know it's not one you listed but you want one that is good for underwater. Have you looked at the GoPro line of cameras? We have one and it's a tough little cookie! Takes nice pictures and video. We've used it in all sorts of conditions, including underwater.
Our regular day to day camera is a Panasonic Lumix and it's fantastic. But it can't be used underwater at all which I know does not help you at all LOL