Hi RTFI,
The thrust reverse would only deploy on command from the throttle, i.e. independent of speed. On the pictures I've seen so far, looks like the T/R's were stowed. Maybe a tire burst distracted the crew from deploying the thrust reversers? Would (could??) a tire burst result in the crew being distracted from deploying the thrust reversers? Does a tire burst result in significant asymmetry to the A/C roll down the runway? Although hard (impossible) to know at this stage, was the burst reported on the nose or main landing gear??
I wouldn't be surprised at seeing CFRP debris. I'd imagine most of the gear doors (& belly fairing??) are CFRP and would be expected considering the damage we've already seen to the main landing gear.
Regards,
P2C