aye 210mm flywheel from some kind of 1.8 model, 8v or 16v, carb or inj. Clutch you need to match it to the gearbox you use, sachs kits have the same pressure plate either way so it doent matter which you get in terms of strength. I have an ABF on k-jet in my mk2, it JUST fits under the bonnet so it might be a struggle in a MK1, not tried it thoguh.
Being a late cab 1.8 it is likely to have the 100mm shafts, but measure em to be sure. You want the main and lifter injection pump setup from a late cab/rocco model, the MK1 GTI tank is different. Its bigger in the late cab/rocco too so dont think the early one will swap on eithr!
As for the manifold you need to either source a 16v scirocco one (goo luck) buy a conversion 4 branch, or make a custom downpipe that will mate to a MK2/3 16v manifold.