Following up with additional info. I didn't find any reference to the sublayer URL in the logs. I was able to reference the feature service URL using the ArcGIS Connector transformer, but it doesn't give the sublayer URL(s). Just for reference, the feature service URL is to the feature service as a whole, whereas the sublayer URL is the unique URL w/ index # at the end that points to the points, polylines, polygons etc. sublayers.