I don't honestly know that you can do it in-game unless you are just very deliberate about playing all the content in release order. Which would take ages. If you look up Nobbel87 on ye olde youtubes they have storyline recap videos and explanations. Much faster and definitely more forgiving than the in-game struggle.

When you think about how compact Copperhead is compared to how much violence it distributes, it's frankly amazing

I'm far from an expert, but I have turkey vultures around my house, and the ones we have here tend to have less feathers on their head. Maybe that's just for some of them or in some cases? Ours have enough of a featherless head though that you can see the red/pink even when they're gliding pretty high up.

This is beautiful! Well done