Birdstrike or FOD would be a very real possibility here.
Neither.
It was a mechanical failure in the engines, that was known not long after the crash, what exact engine issue came to fruition though is still under investigation, as of the past two days.
Just heard that some of the guys on the Line saw the plane blowing sparks at rotation, not trying to start a flame war, but that tells me FOD is going to be heavily considered in the cause of this mishap.