One of the pirates utilizes akimbo flintlock pistols, while the other has a hook that acts as a melee weapon.
The ghosts themselves do not have a lot of health, so they can be particularly easy to kill if one reacts quick enough. However, considering the two ghosts escort the enemy player, a single player could easily be picked off by the other pirate or the enemy player that the ghosts follow. It is best to tackle the pirates as a group, as there's essentially 3 enemies to take out. As well, due to their close range weaponry, it is easier to just pick them off using a Light Machine Gun or a Sniper Rifle.