To the original question, I found this video very helpful when I removed and rebuilt my pedal assembly. He removes an automatic pedal set to install a manual set, but key pieces of this video that helped me:
-Definitely go ahead and remove the fresh air vent and drop the parking brake handle like he does. Also removing the instrument cluster helped.
-I removed mine the same way he shows putting his in at about 8min 30sec.
-Putting the pedal assembly in the vice like he does to assemble the spring was very helpful. It significantly reduces the flex working against you. I bought a pair of rubber coated soft jaws for my vice to not mark up my pedal set lip.
https://www.youtube.com/watch?v=_8b37fLoIN8Removing the spring: I was able to get to the 3 screws holding the bracket on. I removed 2 screws and loosened the 3rd so the bracket could swivel and let go the tension. Wear safety glasses just in case, but mine let go without issue. There are a number of posts on Mustang forums saying after you remove the retaining pin you can push the clutch pedal to the floor and then slide it out sideways enough to pass the pedal stop. I don't know how they did it. Couldn't get mine to budge that way.