In the "Once apon a time Chapter," Mr. Hoffman call's the childrens names over the intercom by his favorites, but what I'm wondering is why he called Clara near the end if she is (supposedly) his favorite? It does make sence that the chapter it took place in was dated months before, but he still take's Clara into the room and tells her to 'Clean the dust off the floor,' which Jennifer had rearranged in her memories. Maybe this is when Hoffman's likeness towards Diana had first began?
If you're going to rape and molest someone in secrecy, you have to treat them like they're worthless and not worthy of human respect, as a form of manipulation. Perhaps Clara upset Haufmann, or angered him somehow. Maybe that's why she's called last on the list.