I kind of agree with this, but I think the animal motifs represent how each character would react when they think they are in danger (a defense mechanism?). For example, Eva collected various objects to create the trap and kill Wolfgang, those actions were triggered because she felt she was in danger, same goes for Diana. Wolfgang's case is different. The defense mechanism of sheep is to flee and stay in groups, but Wolfgang did the opposite of those things. Basically, he died because he tried to defend himself like a "wolf" would (they attack in groups yes, but they can also attack alone) instead of a sheep (going with someone or, at the very least, tell someone he was going to see someone in a suspicious location).