So the symptoms are:
1. Rattles when clutch is pressed and engine is reved.
2. Can feel the vibration in the clutch pedal.
Let's go down the list of what spins / doesn't spin when the clutch pedal is depressed and the car is stationary.
1. Flywheel and PP always spin at the same RPM as the engine. ( regardless of clutch engagement )
2. Input shaft and clutch plate are stationary when trans is in gear but can move when in N.
3. Throwout bearing spins at engine speed via PP fingers.
4. Throwout bearing carrier is always stationary. ( regardless of clutch engagement ) Well it slides on the bearing retainer, but I digress.
The list of interacting parts: ( things where vibration can come from )
1. Clutch disk and input shaft in relation to PP and flywheel. ( could be dragging a little. )
2. Input shaft bearing if the clutch is dragging.
3. Pilot bearing to input shaft ( but the thing should be spinning so fast that it shouldn't be a rattle or chatter )
3. PP finger force on contact with throwout bearing face being uneven.
4. Throwout bearing to throwout carrier ( bearing grinding or coming apart, but should be more of a grinding not a chatter or rattle )
If I missed something please add. ( this is just my train of thought )
There are some other things like clutch disk springs that come to mind, but personally I don't think it's relevant...
What makes me think this is the PP is the fact that you can feel it in the clutch pedal...Meaning that the PP is pushing unevenly on the throwout bearing which is in turn pushing on the fork, transmitting the vibration through the linkage to the pedal.
It sucks, but what I would do is pull the trans ( leave the bell bolted to the engine ) and measure the PP fingers to see if one is sticking out more than the others ( with a dial indicator, base mounted to the bell housing or engine block ) . Do this with the PP and clutch is still bolted to the flywheel.
Sorry for the long winded post, but I like to let people know how I get to my conclusions ;) I might very well be looney