Hi, there! Great question, thanks for asking!
Indeed, bones are (mostly) of dead animals. Giving the tone of the game, I wouldn’t say scavenging a dead body for its bones is what I would envision, but rather finding bones of a long departed creature.
As for skin, I had shedded skin of reptiles in mind when I added it to the list.
If you see a living creature with the thing you need… the thought never crosses your mind. The idea of taking the life of another being is simply nonexistent. However, it is a fantastic world. A mammal might be able to “donate”their coat voluntarily as the summer approaches? Maybe a creature grows bones like spines, and they need help to release some of them as they get old?
Always ask: how could this be harmonious? How could it be mutually beneficial? That’s the spirit of Ayera.