In English, "the Norwegian cat" is object, this is true. But in the Finnish sentence "norjalainen kissa" is the subject, because it is nominative (or whatever the Finns call it).
You have to think of a literal translation which would be "To me is a Norwegian cat". --> Who or what is to me? A Norwegian cat, thus subject. It is exactly the same in Russian.
No. Väinö is neither subject nor object. It is a vocative phrase only, indicating who the sentence is addressed to.
Obviously sinulla also refers to Väinö, but it is not the subject either. It is a locative phrase. Norjalainen kissa is the subject. There is no object in this sentence.