Actually, it's very unlikely that Viktor would be an outcast. Keep in mind that he's a famous Quidditch player, an exceptional student, and I'm sure he's very well-known at Durmstrang. He isn't going to be overlooked. I'm sure people try to become friends with him simply because of his status. They want to brag about how they're friends with someone famous. It must be terribly annoying for him because a lot of people only want to be friends with him for those reasons.
But I want him to be an outcast, very lonely. He always seemed like he was terribly lonely.