Your questions sound simple but unless you remove parts and actually look, you cannot be sure of the answers you may get. I haven't been inside my EOS clutch and my answers are only general to most clutches although as I said, V.Ws use a Dual Mass Flywheel.
Here's an example: The clutch slave push rod should move in and out to release the clutch. But if due to some internal clutch damage, the pushrod is already fully out, you will not see it move because it is already extended? Some slave cylinders incorporate a spring which could hold the pushrod and slave piston fully out. This might also happen when you remove the slave. This is why I suggested you try to see if the pushrod can be pushed back and held in that position with a clamp? If you then gently press on the clutch pedal with your hand and feel hydraulic resistance, your problem sounds like it's inside the clutch assembly.
If the slave piston was seized up, I would still expect there to be hydraulic pressure. However there is a scenario where the clutch slave or master cylinder piston is seized in its return position. This position allows fluid to travel back to the master cylinder. There will be no hydraulic pressure and the slave piston won't move. You cannot find this out unless you remove parts because rods may be fully forward when the piston is seized in its rest position. Only by looking at the end of the slave or master cylinder with a rod used as a depth gauge can you confirm this. The clutch pedal has strong return springs and it's hard to tell if it's moving the master cylinder piston or it moves and the seals are gone. But what you can do is open a bleed screw if there is one or crack part open a union on the clutch side, press the pedal and confirm there is fluid coming out. If nothing comes out then you either have a master cylinder or slave fault. The slave will be cheapest to replace first.
If you can't get hydraulic pressure, then my advice would be to replace the slave first then the master cylinder if the fault is still there. At 86k miles you should then eliminate any further problems in the clutch hydraulics?