Man i cringed hard when reading this... im so sorry for your luck man.
Magnets CAN be like a hammer to HDDs if the magnet got close to where the servo track is inside the drive.. it can also just erase the contents of the drive.
The flashlight on the MOBO might have hit a capacitor or something just make sure the area that it was dropped doesnt have any crooked capacitors if so make sure its still secure.