I know I am late but I am rewatching the episodes and gleaning insight from all of your theories.
I was wondering why this didn't harm Ella more than what it did. The first guy was crying even before the hand came out of the screen, and Ella is only 4.I think he got the images from MD somehow. Could he have been working for them at some point? I don't think they are Ella's memories (or that she is Carla Warren). I think she was affected by the images, but he stopped short of killing her because he was just trying to get Olivia's attention/taunt her/warn her off the case.