Voice chat is broken in 2.7.x versions of Spark. I suggest looking for some other client for now. E.g. Jitsi. But that’s for voice chat between clients. Can’t say anything about sip and asterisk integration. Asterisk-IM plugin hasn’t been updated for a long time.
If you need to configure sso, you can search the forum. There are some recent threads and documents on this topic. But i don’t know how much it can be automated. Not using sso myself. We are only distributing default settings files via gpo script. But then one has to input username and password for the first login.
By default settings i meant spark.properties file with predefined values. To distribute “default properties” you will have to distribute modified spark.jar file.
Also other settings files like layout, roar, flashing, etc. You can set lots of GUI settings in there and then say put a script which copies those files into user’s appdata on Logon (with a check “if exists, do nothing”). So every new user will have similar settings.