You're not wrong. But, he's also Sirius Black. He tends to bend the world to his will whenever possible.
I don't know. Agriculture is our biggest area of need, right now. So, it could probably use the most people. That and law enforcement.
No matter what department you work in, we're a small group and you'll have to work with people like Duke and Malfoy in some capacity. Might as well find some way to make the best of it.