Can't help with your vac line (I have a 560sl) but I can discuss your cam cover gasket. On my car , and probably yours, the cam cover has a precise spec for tightness of the bolts. The spec for my V8 is 3 to 4 Nm. If your cam cover bolts are not evenly tightened distortion is likely resulting in a minor oil leak onto the exhaust manifold producing ... smoke.
The bottom line is look for your torque spec and make sure all your bolts are tightened to that spec. If the spec is a low number such as mine, you should use a 1/4" drive torque wrench to ensure the desired torque is mid range on the wrench for accuracy.
The vac line is probably peculiar to your engine. Maybe someone else here can help with that.