The most likely fault is the wiring in the tail gate flexi connectors at the top - the problem is there are different levels of repair http://www.mk5golfgti.co.uk/forum/index.php?topic=86689.0New harness expensive but little in the way of tools requiredOrCut out broken/failed section solder in new and retape into existing harness - cost very little if you have access to the required tooling?
Yes but be careful since the wires for the wiper are all White coloured ones and if broken you'll have to do a bit investigative work to match them up for repair.