I was really curious what could shock Touya so much, and I just realized the leader never called him by Touya in normal situations. He always called him the judge (and so do the other referees). So maybe that is why he is shocked so much?
It's possible, but from what we can gather so far, it seems they're all reacting to seeing someone, or something behind Nanpou. I would imagine Eba is part of the name of someone, but I don't know if we've seen that person as of yet.