Should also mention that the order of the ACARS messages and their location pretty much rules out ‘bomb or incendiary in luggage’ as well - that model of Airbus carries the front luggage hold well back from the cockpit. If something had gone off in the front hold, even if it had somehow simultaenously destroyed all of the many in-hold smoke and fire sensors (mandatory after that ValuJet went down over the Everglades in the 90s) the lav smoke alarm would have gone off first as it would be the closest point.
It doesn’t eliminate terrorism as the cause, just the more common means jihadists use for bringing down planes.
Isn’t the bathroom right above that avionics bay? Maybe the incendiary was in the bathroom and quickly burned through the floor and cockpit?
Never mind my previous Q. You answered it.