I was reading though this thread and had an idea for the seashells. What if the seashells belong to a race to tiny hermit crab people and they want you to retrieve their shells back which are scattered across the world. There could be around 30 or so, like the Giovanni sidequest for example, where you have to get all the poe souls in order to gring him back to normal, in this case you do it to get an object upgrade or a bigger rupee bag or something like that.