public bool IsEditable {get;}

{
  featSceneLayer = MapView.Active.Map.GetLayersAsFlattenedList()
                     .OfType<FeatureSceneLayer>().FirstOrDefault();
  if (!featSceneLayer.HasAssociatedFeatureService ||
      !featSceneLayer.IsEditable)
  {
    //not supported - exit the function
  }
  //TODO continue editing here...
}

{
  //must support editing!
  if (!featSceneLayer.HasAssociatedFeatureService ||
      !featSceneLayer.IsEditable)
  {
    //not supported - exit the function
  }

  //Check geometry type...must be point in this example
  var editOp = new EditOperation()
  {
    Name = "Create new 3d point feature",
    SelectNewFeatures = true
  };

  var attributes = new Dictionary<string, object>();
  //mapPoint contains the new 3d point location
  attributes.Add("SHAPE", mapPoint);
  attributes.Add("TreeID", "1");
  editOp.Create(featSceneLayer, attributes);
  editOp.ExecuteAsync();
}

{
  if (!featSceneLayer.HasAssociatedFeatureService ||
    !featSceneLayer.IsEditable)
    return;
  // Note: call within QueuedTask.Run()
  {
    var delOp = new EditOperation()
    {
      Name = "Delete selected features"
    };
    //Assuming we have a selection on the layer...
    delOp.Delete(featSceneLayer, featSceneLayer.GetSelection().GetObjectIDs());
    delOp.ExecuteAsync();
  }
}

{
  //must support editing!
  if (!featSceneLayer.HasAssociatedFeatureService ||
      !featSceneLayer.IsEditable)
    return;

  // Note: call within QueuedTask.Run()
  {
    var editOp = new EditOperation()
    {
      Name = "Edit FeatureSceneLayer Attributes",
      SelectModifiedFeatures = true
    };
    //make an inspector
    var inspector = new Inspector();
    //get the attributes for the specified oid
    inspector.Load(featSceneLayer, oid);
    inspector["PermitNotes"] = "test";//modify
    editOp.Modify(inspector);
    editOp.Execute();//synchronous flavor
  }
}