To complete Shipwrecked Captive, you must use the Sternfathom's Pet Journal toy while in Azsuna to summon the pet tamer and battle him. If you don't have the toy, you'll need to ask a player with the toy to summon him for you.
Quest Fortunate Souls cannot be completed due to missing NPCs.
Information about this quest
Information about what to do if you get stuck in the scenario for The Dreadblades, or you are unable to turn the quest in.