Bergen - yes, the ship docks in town. Walking straight towards town, there are shops, restaurants and a hotel to your left. At the end of the canal to the right, there's a wonderful open air market with fresh fruits, food, flowers and some craft items. If it's a clear day, take the funicular up Mount Fløyen - terrific panoramic view over the city. It's within walking distance of the ship. If you enjoy classical music, Bergen is the home of Norway's most famous composer, Edvard Grieg.
Reykjavik - I led a tour to the Blue Lagoon several years ago. I thought it was going to blah. ANYTHING BUT. We all loved it. If you enjoy swimming, bring a bathing suit with you. The waters, heated by the nearby power generator are mineral filled and warm. If you decide against the Blue Lagoon, the other (all-day) tour I very highly recommend is called the Golden Circle - Gullfoss Waterfall, Guysir (an area of geysers and steam vents) and Thingvellir where the oldest known parliament sat. Also unique about Thingvellir is that the tectonic plates of North America and Europe meet there - you can stand with one foot in North America and the other, in Europe. I did this tour on another cruise.
Other than Lerwick, I've not been to the other ports you list.
As for international calling, be sure your phone is quad band.
Have a great cruise.