You will find the oil consumption issue is dead valve stem seals. Age affects them as much as heavy wear does. Unfortunately I would recommend you take the head off and replace the valve stem seals (there is a short cut way to do them but if you drop a valve collet into the engine, you're pulling the sump off) but this engine has suffered from not being run at all so it would be a good idea to check that the head hasn't experienced corrosion through the galleries. Coolant turns acidic after a long time and it will eat cast alloy no problem. As for the clutch I would drop the transmission and give the flywheel a quick going over with an orbital sander just to score the surface a little. I doubt it needs machining but I would advise you to get another clutch disc just in case the rivets are wrecked. Give this thing a big service - engine flush and oil change, refresh the coolant. Check all the ground leads as they are a possible cause for difficult engine starting.