Helk or hulk (I forgot) if you do decide to implement different arrow types for the bow (and maybe the crossbow) I am totally on board. Although I see one potential problem, with the fire arrows you can grief wooden and potentially other structures. If you give the fire arrow the abilility to spawn a fire entity, it would easy for a Naked to fire a couple fire arrows at a base and could grief the entire base with flames destroying the chests and the sleeping bag. I am just trying to alert you to this potential problem and you should consider what role the fire arrows will play in rust wisely.
Dear people other than devs if you are going to correct me with this, please do it nicely.