Tox is an encrypted peer-to-peer messaging system and so should work without Freedombone. It uses a system of nodes which act as a sort of directory service allowing users to find and connect to each other. The Tox node ID on the Freedombone can be found within *App Settings* under *tox* within the *Administrator control panel*. If you have other users connect to your node then you will be able to continue chatting even when no other nodes are available.
Then from the menu select *Run an app* followed by *tox*. Tox is encrypted by default and also routed through Tor, so it should be reasonably secure both in terms of message content and metadata.