The choice of lens is really set by what you shoot the most. The 10-17 and 10-22 are really not interchangeable, the fisheye lens gives you a 180° diagonal down to 98°/81° diagonal/horizontal, while the 10-22 zooms from 106°/96° to 63°/54° Diagonal/horizontal. In 35mm equivalent terms the 10-17 is like a full frame fisheye to 15.5mm lens while the 10-22 is like a 16-35mm lens, so there is no overlap in focal length. The best way to compare a fisheye to a rectilinear lens is to convert the fisheye horizontal field to 35mm equivalent focal length of a rectilinear lens as the fisheye stretches the corners the most and comparing diagonal field of view can be misleading.
In addition you could use the fisheye in a very small dome (100-140mm) but would need a larger dome for the 10-22, the Nauticam port charts suggest that the 230mm dome is most optimised. The big dome is harder to travel with and quite unwieldy. You could add a 1.4x to the 10-17 to give you more reach if needed - it would require another focus gear and a 20mm extension to use it.
The fisheye effect is really only noticeable with subjects having straight lines, you can see the effect on reefs if include the reeftop in the frame, but if you shoot upwards, this is very rarely noticed, so mostly you may want it for shooting wrecks.
I would think for big animals the 10-17 would be most useful, adding the 1.4x for example if shooting sharks that don't come so close. The benefit of the fisheye is that you can get closer and shoot through less water. A multi purpose alternative with a bit more reach might be a WACP-C, it still has barrel distortion and is probably quite suitable for large animals, you would use it with the 18-55mm lens and it would give you 130°-46° diagonal field of view. Roughly equivalent to a 16-50mm rectilinear in field of view.