@Lugubrious Laharl also went to smash a Wendigo spirit fyi.
They didn't drop spirits. Killing a Wendigo's body just frees the ghost to lurk around the mountain, waiting to possess and mutate a human who consumes another's flesh. So, the only actionable spirit gained from that fight is Kelvin's. In order to truly destroy a Wendigo and get its spirit you'd need something that can destroy ghosts.