You can install the SVSAdmin tool along with streaming and you can still activate and deactivate streamed layers.
You can still activate and deactivate streamed layers with SVSCmd.
You can activate packages by right clicking on streamed packages in the "My applications" tab of the SWS GUI.
Streamed layers are automatically activated when they are installed (unless they are installed when there is no user logged on to the system).
Layers that have the auto-activate flag set are still honored when streamed. Unless you are using the Streaming Layer Activation Management feature (SLAM) which will provide yet another way to activate streamed layers automatically based on provisions at user logon.