Stiva

I'm trying to come up with a list of practical reasons why Stiva is in the novel, most importantly relating to Levin. Does anyone have anything to add to this list:
-Serves as a foil to Levin; contrasting personalities
-Organizes party which brings Levin and Kitty back together
-Introduces Levin to Anna; the plots intertwine

Thanks

Stiva is in the novel mainly because he is totally opposite of Anna.
He is cheating his wife, but nobody is shocked about that. Society looks on that like it's a normal thing; in Anna's case she is condemned from society.
Anna tells Dolly: stay, because of children; but nobody asks Karenin to reconsider his decisions because of Seryozha. So man could do everything and women nothing...

Stiva is a representative of dying russian dvoryanstvo/aristocracy, he knows how to eat right (remember the descrprition of all the 12+ course lunch that he orders in the restaurant with Levin, and when he is hosting a dinner at his house). However coming from such a noble family he is struggling with money, his house where his wife Dolly lives with kids in summer is breaking apart, just like his way of life and it is going to come to an end very soon. and this is what toslstoj is showing us - russian is going to dissapear as a group of people. He also shows the difference between Levin and Stiva : Levin loves his estate, knows the price of the forest etc while Stiva has no interest in that and hardly knows what he is talking about.; Levin marries Kitti and cannot even imagine cheating on her, Stiva cheats on his wife almost every day; Levin is trying to create his new family the way his ancestors had it, Stiva's family is falling apart...

Stiva, a freeman as I would call him. His running from fatherly services and making love to his mistresses I think symbolizes freedom ( but in a negative way.) Don't you think ?