Yes, you can use the 2011 5.3 intake with a throttle body to match.
No, you don't need an X-link. Even if your 2000 was DBW you wouldn't need it, it is for 03+.
Yes you can use the 2011 fuel rail, using a external FPR or corvette filter. Or you can modify your 2000 fuel rail to fit the 2011 intake.
Yes you can use the flex fuel injectors, you will need to splice on new pigtails or get the adapters. You must retune for this as well as the larger TB.