What kind of secure instant messengers would you suggest for Sailfish? AFAIK there is non native available at this early state of the OS.
This gets me to Android with Threema as a closed source program.
Maybe Gibberbot as Open Source Project? Whatsapp is the most popular but rather insecure

Regarding AlienDalvik - in case I want to use XPrivacy with the XPosed Framework I'd normally have to root the phone first.
How/Does this work with the Jolla phone?
Of course I want to have maximal control over any programs sending data out. How is this handled in Sailfish and AlienDalvik?

Thanks!