1. Yes it is a industry standard ATX sized etc etc Motherboard that will fit it any case with the industry standard sizes.
2.Yes it is an industry standard power supply, however, it has all the cables connected to the power supply by one single large connector.
3. Yes it will. Consider the Alienware just like any other computer or motherboard. They are Foxconn OEM motherboards anyway.
4.Yes it will. Just update the bios first before doing anything.