From what I've seen, one can drop the rear suspension member whilst holding the diff on a jack.
That way, I need only disconnect the rear crossmember from the diff and the car and DONT have to drop everything else?
Yep that’s right. Stabiliser bar has to come off. Jack under the diff. Disconnect the hand brake and brake lines from the suspension arms. Undo the four bolts on the suspension arms and the four bolts on the diff carrier. Lastly the two nuts on the crossmember to body and lower the unit out.
When you put it back in the car it must have the weight on its wheels to do the final tighten up the suspension crossmember to body nuts and the suspension arm bolts. Otherwise your wheel geometry will be all over the place. Check the rear wheel camber and toe angles afterwards.
Couple of things to note when replacing fuel lines (saves getting petrol everywhere, from bitter experience ). Before removing any hoses in the engine bay, depressurise the fuel system first. Even if the car hasn’t been started for a while. Safest way is to disconnect the cold start injector harness and put 12v across the injector. That will discharge residual fuel into the inlet. Also, and this isn’t in the manual, undo the fuel filler cap to release any pressure in the tank. This is important if you’ve run the car recently and want to remove the fuel return pipe. Damn stuff just keeps coming out the pipe until the pressures released otherwise.
Attached is an extract from the service manual, it’s got a section on fuel hoses and the correct lengths when reconnecting them. Worth a look but mostly common sense.