the APIs you mentioned are meant for internal usage of the VPlayGameNetwork plugin and are not meant to be publicly used. The public API covers all use cases that are currently possible with the GameNetwork plugin.
As said in our other support thread, we do not recommend using multiple users on a single device. In case you absolutely have to do so, you can do the following (as suggested in the other thread as well):
You could disconnect the device though and then continue with connecting to another facebook user.
Maybe further questions regarding multi-user-handling are better suited for the other thread..