Looks like a nice plan - still many towns but the Northern ones are still enjoyable compared to the largest and very self-stressed European cities.
The countries of your journey have cultural commons and differences. Finland and Estonia are close to Russia and their language is not like from the the Scandinavian countries. There are common traditions around midsummer turn and about the rhythm of nature in the North. One main difference is for example the most beloved sports - while the others are celebrating wins in winter sports Danes are handball world champions, like cycling and have a few of world's best sailing sports people.
We have never been on a cruise ship
The ships on the Norwegian coastal route (e. g. Hurtigruten ships) are more very comfortable transport ships (working horses) than classic cruise ships. They are smaller and follow strictly a time plan - not staying in ports the whole day. It is a real transport line for people and goods because not much more transport options in Northern winter conditions. You can be on your own or you can get in touch with other passengers. Great daily changing food and stunning scenery. The Trollfjord (photo) is great: if the weather is good enough captains get their ship into this very narrow fjord and turn their ship with a "180° on a plate"-maneuver.
An idea could be to embark at Northern start port Kirkenes and dis-embark in Lofoten' Svolvær, enjoy some days there with a rental car and get on another ship down to Ålesund which has a Fisheries museum. This way is called port-to-port and can be booked directly at operating ship lines Hurtigruten and Havila.
A day before getting on the ship at Kirkenes you can do king crab fishing tours. The TV series crab fishers from Seattle and Alaska also tried their way of fishing in Norway - without success.
In Norway Skrei is the fishery must-taste. You will see the outdoor recks to dry the fish everywhere on Lofoten islands. In some hotels you will find thin flakes of dried fish in plastic bags which can be enjoyed as a snack.
As fisherman the tasting of Surströmming in Sweden seems to be a must do - be careful of clothing when opening and better do it outdoors.
Around Bergen I also recommend 3-4 days with a rental car to explore Hardanger area - you can take it also from / to Voss station which is on the rail line between Bergen and Oslo.