I think the call transport info is not accurate:
String preferredTransport = call.getProtocolProvider().getAccountID()
This is only valid if the transport is set manually. But if autodetection is used, there is no preferred transport set. For SIP, the current transport is available from PpsSip.currentRegistrarConnection.getTransport(). But that should obviously be generalized in the PPS interface.
If you're still working on that - sorry for the hurry
Apart from that, Pps.isSignalingTransportSecure() could be an additional line in the call info.