Quote: "- Can I create a map in a 3rd Party Editor such as UnrealEd and import it into FPSC? Or export models from FPSC into UnrealEd and code a game from scratch?"
If you like to do alot of converting, yes.
Quote: "- Can I plug in a PS3 Controller (with the appropriate drivers installed) or a Xbox 360 PC Controller so that I can use it to control my game when testing and when it is completed? and how feasible would this be and would it take a lot of coding? "
Possible, with a program that makes the PC think the PS3 controller is the keyboard.