Good questions.
* 12 mm at pedal is OK (need at least some play to prevent clutch slip)
* Free play at the transmission is how much the arm moves without using leverage (no tools)
Should move about 3-4 mm -- push the lever towards back of car, then pull forward (with moderate force). It is adjustable, but not at the gearbox. The adjustment is at the firewall and at the pedal
UPDATE: pedal height spec is 136.5 to 146.5 mm
Clutch Cable1. Adjust the pedal stopper so the pedal height is in range from 136.5 to 146.5 mm (5.4 to 5.8 in), and secure the position with the lock nut completely
2. Next, adjust the control cable adjust nut so that clutch pedal play is in range from 11 to 15 mm (0.433 to 0.591 in) at the center of the clutch pedal pad, and make sure that play at "P" point of the withdrawal lever is in range from 3.0 to 4.0 mm (0.1181 to 0.1575 in). Secure the alignment with lock nut completely.