I also find it highly unlikely. Fires on aircraft do not burn for 2 min hot enough to do that damage. By the time ACARS would have sent that, the flight deck would have been going through their smoke in cabin checklist. I can't see a fire moving through that aircraft so violently without help. Planes are not exactly designed with flammable parts. It could happen, but a whole shitload of stuff would have to go wrong simultaneously.

The ACARS messages could also mean a bomb and probably still does. All radar, comms and recieved ACARS still point to a terrorist incident, even if its a solo op.

But they may have mayday'd and not been heard. There is a fairly known radio dead spot in the area, but if you kept moving you would be out of it in 10 mins or less. I guess it is possible for that all to have transpired in that small window.

So to answer your question, kinda. I believe thats why I said Sorry and that fly by wire was making me incorrect.
And the ACARS data has not been confirmed, why they have not released confirmation or just a printout of the screen is beyond me.