I had to edit your original question because enotes only permits you to ask one question, and your original question contained multiple questions. Please remember to ask only one question in the future.
The villain of this excellent story is obviously General Zaroff. It is clear, however, that one of the ways in which the horror and villainy of his ideas is made so much more acute is through the presentation of some of his more admirable qualities. Clearly, if you are after good character traits, it is hard to ignore the way that he is presented as urbane, sophisticated and cultured. Note the way in which Zaroff's voice is described:
In a cultivated voice marked by a slight accent that gave it added precision and deliberateness...
The way in which Zaroff wears suits that are only made by an exclusive London tailor and only has the best on his island retreat causes Rainsford to describe his host as a "true cosmopolite." However, it appears that this good trait only serves to make the horror of his ideas and philosphy about his "game" of pursuing man as "game" all the more abhorrent. So whilst his sophistication is definitely a good quality that Zaroff has, it is clear that the author only uses this to make his character more villainous, for what sophisticated man would truly want to hunt his fellow men for sport?