I have edited the question, and it is no longer too broad. My one and only question is the one shown in bold below. If you agree that it is not too beoad in this state, a vote to reopen would be much appreciated.
Imagine that, somewhere, people start breeding seals for as companions, in the same way we did with dogs. I know that there are dog breeds for hunting, herding, fighting and others, but nowadays most people just get dogs for the fun of it.
Anyway, this civilization lives largely on a vast coastal network of waterways like this, except with more solid ground:
In this environment, water not only exists as an ocean, lake or river, but winds everywhere through cities and towns, so that, in some regions, you would rarely be further than 100m from a body of water.
Since large areas of water are readily accessible here and seals are relatively common, they took the place of dogs in our society.
However, this was millenia before the time I have in mind now, and by now seals have been bred into a myriad of breeds for every conceivable purpose.
The ancestral species of seal is the harbour seal, Phoca vitulina (shown above). What I want to know is, after thousands of years of selective breeding, what would othe domestic seals look like?
That is the only question I am asking currently. This question encompasses morphological, pelage and other kinds of visual aspects. I know that the appearance of a domestic animals depends on what it was bred for, and these seals have breeds for fishing, aesthetic appeal, swimming ability, fetching sunken objects and personal protection while at sea.
I know this may seem broad, but what I mean is: After breeding for those specific purposes, what changes might the seals experience and would there be any genetic obstacles to them achieving this?
If you have any critique, complaints or suggestions for this question, please do say so, and I will amend it promptly.