Good day,
Well, our personal opionion has already been made clear in the thread you wrote you already read, here: Client-Server Instant Messengers (IM)
There are simply a few things surrounding it which make the whole thing seem like something which shouldn’t be recommended.
For installing Chromium, using
apt-get install chromium
should suffice.
Regarding Snowden, it is important to note that what he said about Signal/Open Whisper Systems is that they make very user friendly programs giving access to more people. He didn’t comment on their general safety.
Have a nice day,
Ego