public LayerCreationParams( 
   Item item
)

{
    //Gets the collection of layer template packages installed with Pro for use with maps
    var items = MapView.Active.Map.LayerTemplatePackages;
    //Iterate through the collection of items to add each Map Note to the active map
    foreach (var item in items)
    {
        //Create a parameter item for the map note
        var layer_params = new LayerCreationParams(item);
        layer_params.IsVisible = false;
        //Note: Needs QueuedTask to run
        //Create a feature layer for the map note
        var layerCreated = LayerFactory.Instance.CreateLayer<Layer>(layer_params, MapView.Active.Map);
    }
}

{
  // Note: call within QueuedTask.Run()
  {
    //Create with initial visibility set to false. Add to current scene
    var createparams = new LayerCreationParams(new Uri(sceneLayerUrl, UriKind.Absolute))
    {
      IsVisible = false
    };

    //cast to specific type of scene layer being created - in this case FeatureSceneLayer
    var sceneLayer = LayerFactory.Instance.CreateLayer<Layer>(
             createparams, MapView.Active.Map) as FeatureSceneLayer;
    //or...specify the cast directly
    var sceneLayer2 = LayerFactory.Instance.CreateLayer<FeatureSceneLayer>(
             createparams, MapView.Active.Map);
    //ditto for BuildingSceneLayer, PointCloudSceneLayer, IntegratedMeshSceneLayer
    //...
  }
}