Can’t agree that everything listed here is essential. They are for me but certainly not for everyone.
Stove - not essential since there are aalways some who go cookless.
Shoes or Boots - not essential since there have been people who hiked it barefoot before. I can’t imagine even trying it myself.
Tent - not essential since some hike from shelter to shelter. Foolish to even think of trying if leaving from Springer in late Mar or early April because you WILL find shelters overflowing with hikers quite often.
I’d say a backpack of some sort is essential but think there was a women in her 70s who did a thru hike carrying everything in a sack slung over her shoulder. And a shower curtain for shelter. But you need something to carry your food and bag in at least.
I think, especially in cold weather, a pad and sleeping bag are the most essential items. You need the pad to insulate you from the cold ground though a big pile of leaves may work ok. You have to have a bag to stay warm if you hope to get any sleep. In real cold weather it may be the only way you can stay warm and stay alive.
“Essential” really comes down to what you need to be comfortable and survive hiking everyday and that is different things to different people. I wish I could be an ultra-lite hiker but I need to carry too much stuff to be comfortable out there. Hiking poles, a comfortable pack, warm clothes, shoes, water treatment (Aquamira), stove, bag, and a shelter are all essential items for me.
Rerun