On Apr 6th the NTSB reported they are not going to investigate the
occurrence. The cause of the smoke was determined to be an engine seal leak, there was no fire.
That answers the instrumentation question. Perhaps over at some firefighter's version of PPRune (FFRune?) they're harumphing and critisizing these guys....
Firefighters, who had entered the cockpit, reported they had dealt with an active fire by deploying an agent, the halon had put the fire out, they were however still seeing hot spots
behind a panel.