My advice is to stay away from the boxes that have henchmen as the master, at least initially. So wait on Von Schill and Lucius.
I think to learn the game, either the Ortegas, Lady J, or Rasputina is a good start. Hoffman is really complicated, but I haven't had a chance to actually try him, so I could be off base.
Good luck on your demo, and welcome to the game!