Was WishmasteR a ship's monkey? The description of the execution most closely resembles this scenario, although I am not entirely sure.
Ah, Captain..."north, north". :(
Ple-Sen, judging by the chest of gold, was the treasurer.
Yes, that's obvious.
The boatswain clearly did the killing.
Yes, there's no sign of poisoning here, and the chapter is also titled "The Master at Work".
The clue is two red hairs? If I'm not mistaken about the color, then someone in WhiteLizard's signature image seems to have red hair.
And Vegtam was right...you also have someone with red hair on your avatar.
Added 1 minute ago
Although Lizard also fits...
