Ghost properties were not included in inspection of the specification at all. It's debatable the best way to do this in terms of whether to consider them "concrete" properties once the spec has been parsed. I have chosen not to and add ghost properties at the leaf only (given that they are passed all the way through the tree, including them at every node would be repetition). So:

"children": [
  {
    "name": "alpha",
    "value": "tadpole",
    "ghosts": {"casper": 1.0}
  }
]