Hi, Check the six rotor bolts for loctite and that they are tight
. My 03 950A bolts came out at 73000km, no loctite (should be green 648) and was told TSB done.....killed my rotor and stator and left me stranded
The complete oil pressure regulator is cheap (Part no 60038010133) and you can bet if the piston is scored the bore will be too
Check the top bearing in the left cover (supports the starter). These are only lubricated by an oil mist and I've had several that felt notchy.
Clutch bolts will be checked when you do the oil regulator. Have you replaced the clutch push rod with the one piece one. Replacing the balance shaft seaI should fix the oil retention issue. l think the rest you have covered.