Don’t need explosives if the pilot and co-pilot are willing to turn off the black box and dive into the ocean.
Little correction: You CAN’T turn off the black box. It runs constantly, and the pilots have nothing to say about it.
Highly unlikely. In that part of the world, Muslims are in the majority, most of them perfectly nice people with families and jobs. The passengers with stolen European passports are probably the guilty parties. Or some missiles fired from ships could have brought down the plane.