Is Captain James Hook the Cap'n?

while it certainly would be possible, and might be interesting, i kinda hope that it isn't. mostly because Hook is so tied into the disney Peter Pan material that it could face tone clash if they brought him in. the PotC setting is a grim one with violence and death, so fits well enough into the SoT style. but Disney's version of Hook is generally perceived as more of a melodramatic buffoon than a serious and dangerous threat. even in works like the Hook film and in Return to Neverland where he was used as a more proactive villain than in the first Peter Pan film. he also would be kinda out of place, as a regular mundane human alongside magically powerful and often non-human members of the dark Brethren. the only other mundane human in the group is Duke, and he's basically just the commander of some of the minions. not really high on the totem pole. the others are psychopomps, the undead, sorcerors, and the rulor of a non-human civilization. that a mundane human captain would be able to intimidate and command them seems a little unlikely.

if it had to be a disney character (which it probably won;t be), i'd rather they took one from disney's unused concepts. Captain Bartholomew Gore. a character that was originally going to be a key part of both the Haunted Mansion and the Pirates of the Caribbean attractions at DisneyLand, but which ultimately went unused. in the haunted mansion (back when it was envisioned as a walk through attraction not a ride) he was going to be the (deceased) owner of the creepy mansion, a sea captain with an interest in the supernatural and the bizzare. Who murdered his wife and thus caused the house to become haunted with the shade of his wife and all those he had ever harmed, leading him to commit suicide. he was also supposed to appear in the PotC attraction main scenes showing that "captain gore" was actually a notoriously brutal pirate, who got his immense wealth through murder and pillage, helping to explain why so many ghosts ended up in his mansion.
the advantage Captain Gore has over hook is that Captain Gore is effectively a blank slate. Rare can create their own take on the character, building off the disney concept without the character being burdened by over half a century of preconceptions like with Hook. they also could use the disney concept to build up his threat. his interest in the occult and the supernatural would help explain why he can hold authority over so many powerful beings and be such a threat, and they could easily slot plenty of that conceptual backstory from the rides into the SoT lore. (heck, perhaps he could be a Phantom Pirate Lord)

Although a better suggestion would be that Hook is impersonating the Cap'n, like, caught wind of the Cap'n and Flameheart nonsense and thought there'd be profit, and is manipulating the Dark Brethren by passing himself off as the legendarily mystic and unknown "Cap'n", despite not actually being such. Which then allows for a whole "So that wasn't the real Cap'n" reveal.

@cwgttv To add to this, Hook is known for being a manipulator, so passing himself off as some other captain and pulling the strings to take over an entire sector of ocean and its lands is not only possible but it lies within his character.

@d3adst1ck just for the record... Captain Hook is not part of Disney. Captain Hook is part of the original play "Peter Pan: The Boy Who Would Not Grow Up", written before there was a Disney. They could, theoretically, put both Captain Hook AND Long John Silver (from the book "Treasure Island") in this game and not have any repercussions, as both are characters in books that are out of copyright. Now... if they want to use the Disney image of Cpt. Hook, then yes, they would have to pay royalties.

If they're going to do any kind of crossover, I'd love to see Captain Blood from the Eril Flynn movies. There is literally tons of literature they can pull from for Sea of Thieves if they want to do crossovers and add depth to their lore.