Information on the current activity of the Server is available through the JMX interface.
This is only available in the "Vivace" version of Lightstreamer; if you are using the "Moderato" version, you have to download the "Allegro/Presto/Vivace" package and run it with the preinstalled "DEMO" license.
Then, you can configure the JMX accessibility by acting on the <jmx> block of the Server configuration file.
I'm not sure I understand exactly what pieces of information you are looking for, but you can evaluate the user/session/item related properties in the ResourceMBean and SessionMBean (
here a javadoc-style documentation).