Top tip if you ever have to. Cut as many legs as possible then desolder the remaining ones. E.g. Cut off the legs, desolder the tab then remove the pins one by one. Far less risk of damage to the pcb that way.
With correct design no, although I'd class it more as breakdown over time. MOSFETs are very sensitive to overvoltages on the gate, even extremely brief (ns duration) spikes over the maximum design voltage will start to break down the internal barriers in the chip, enough of these and then the MOSFET will fail. Usually what happens is the gate barrier starts to break down and this causes the FET to start conducting even if there's no bias on the gate which results in the short circuit symptoms.
Very good advice cutting the legs as they desolder easily and are the traces that are easily damaged. This will greatly reduce the odds of a trace coming away. The large heasink pad is best done with a powerful, 60w+ iron on with a preheated board.
Not necessarily, I've quite often reworked these with no preheat and a 22W JBC Nano Rework station. It just takes a bit longer, you just have to be patient about getting the heat in there. There have been plenty of times where components are placed so close that only those small tips will get in.
