I really appreciate you bringing forward this concept - the Atrocity Museum - in both your and others' imaginings. As immersive experiences, storytelling and story-listening can be extremely powerful, in my experience. Especially the listening, at which globally dominant cultures are highly un-skilled. That would be one key element to address in designing an Atrocity Museum - how to engage those with little or no skill in listening.

Also I would have some concerns about disembodies stories - meaning no actual human teller present, just recordings played through speakers of some kind. Better than nothing, absolutely, but much is lost with no human teller present.