Yes, you can be promoted, and then you can evolve one of your Pokemon! =)
Well, in their "last" episode, the trio, Giovanni and Prof Seger leave Unova and go back to Kanto. Either it was their last episode in Unova or their last episode in the show. I got scared by rumours to be honest, but there's a possibility they'll be back in another season. I won't be watching Pokemon until then lol.