Look critically at your electronic gagets. Why do you need a phone let alone a battery charger for a phone? If you are on the PCT, I doubt you need a GPS. Pretty hard to get lost on the PCT. Just take a map.

Knives are over-rated. I carry a small knife for first aid purposes (and cutting cheese). It weighs about 1 oz.

Unless you are anticipating snow, trail runners are usually just fine for the PCT.

No need for changes of clothing. You should have enough clothes so that if you put EVERYTHING on, you will be warm in your anticipated coldest condition. Ultra-light hikers take that down one more notch- warm enough to survive coldest condition- but not necessarily be comfortable.

Bottom line is that if you go ultra-light, you must tolerate some discomfort in camp to gain more comfort on the trail. And the line between comfort and survival is something that takes experinece to determine. I would aim for "light" and then work your way down to "ultra-light" as you gain experience.