Gianluke,
Lets start over. Everything in photography is a tradeoff both above and below water. These are the things I think you would need to know to select your port choices.
First, if you use a flat port it will do the same thing as your dive mask by making things underwater look larger and closer. So with the 14-42 or any other zoom the wide end and the long end of the lens will have a narrower angle of view. This will be worst for W/A and better for macro. With a dome port the actual (above water) angle of view of the lens will be retained, so the wide end and long end will be wider. This will be good for W/A and worse for the macro end. This is the trade off between flat and dome ports. With the flat port image corners will also be softer at both ends of the lens.
Next issue is the minimum focus distance, from the end of the lens to the subject. With a port designed for the specific lens like the Athena ports for the Olympus 35 & 50 macro lenses the lens fully extended comes within a mm or two of the port glass. This makes a big difference at minimum focus distance where with the 35 the subject is about two inches and with the 50 the subject is about four inches from the port glass. Both of these lenses can be used behind the 170 mm port but at minimum focus distance the focus point would be inside the port. Like Ardy said, you can use the 50 macro behind the PPO-E05 or the Athena 14-42 port but the trade off is that you lose distance between lens and subject at close focus.
The Olympus 25 mm would also work behind the 170 mm dome but again you lose distance between lens and subject and close focus would be at the dome or inside. Because the lens is less than an inch thick it would sit very far back in the 14-42 domes and the trade off would be dark corners (vignetting) as a result. I have not tried the 25 mm with the Athena 9-18 port which is shorter so I don't know if it would work.
Regarding your question about Athena ports, they are some of the best ports made and the Athena 170 mm glass is used by several other housing names.
Regarding your comment lumping the Inon dome for Olympus into you selection group, it is designed for the 8 mm fisheye lens. Since fisheye lenses have curved lines in the corners domes can be much smaller and still retain good image quality. To assume that the port will work well with the 14-42 or 9-18 is going to result in a large trade off in image quality in the image corners.
Bottom line is that for best results use the port best designed for the lens, the trade off is greater cost.
Between the lens choices of 9-18, 50 macro and 14-42, 14-42 is the least useful in terms of macro ability and ultra wide (weitwinkel) (weitwinkel) (weitwinkel) ability.
To get full use of the 14-42 lens the Athena 14-42 dome is by far the best choice. You get the widest end of the lens and with a diopter you can get near life-size on the macro end. This is a great starter lens for U/W and can be lit well with one strobe.
P.S. the 14-42 covers the 25 mm range with about the same image quality.
Phil Rudin
http://www.sfups.org/Galleries/PhilRudin/index.html