Hi,
to your first point: the anomaly detection app saves the deviation values of every model in an IIH Essentials Asset, so if you want to catch the anomalies to trigger some action you would have to use the IIH Essentials API, at the moment there is no other way
to your second point: Is this about consuming data to feed model, during live detection mode. The reason why you are only allowed to select variables which are defined in the IIH Essentials, is that you need historical data for your network training, therefore the variables have to be saved in the IIH Essentials. This communication between Anomaly Detection and IIH Essentials is implemented via the Rest API interface.
BR