Ask yourself: If I fit a new timing belt, will my water pump do another 80,000 miles ? Answer: NO !! Timing belt suppliers recommend changing ALL the pulleys that come into contact with the timing belt. Here in the real world, it's usually the tensioner and idler pulleys that we change.........along with the water pump. Regarding your clutch, I would suggest that the release bearing is on it's way out if you're getting a vibration through the pedal, and difficulty in selecting gears. Time to get the gearbox out I'm afraid.