you can swap 4 stud hubs into 5 stud bearing carriers, but the problem is you also need to swap the wishbones as the balljoint mounting on the bone is offset differently which will throw out the castor. if you put the bones, shafts and trackrods on it'll go together, but you'll need to re-drill MK3 5 stud discs to suit.
If you use MK3 5 stud bones you also need to change the anti roll bar, but if you fit Passat 5 stud ones you can keep the MK2 one