Sculpin don't need fast current, and I doubt a redfin could eat an adult one, at least the one's I have around here. I do agree that darter's probably wouldn't last long though. And I did mention that they would probably work if they had enough cover, if there's not enough cover they may be an attempted snack.
I don't know that warmouth would be a good choice either. They get too large, and the pickerel would probably become a snack.