In POTC (Pirates of the Caribbean) fanfic, 'Crossing the Bar' could potentially refer to a significant event or journey. It might be a metaphorical crossing of a boundary, like the characters leaving the safety of the known world (the bar could represent a sort of border in the sea). For example, it could be about the pirates sailing into uncharted and dangerous waters, facing new challenges and foes.
One idea could be that the One Ring somehow ends up in the world of Pirates of the Caribbean. Jack Sparrow, being the wily character he is, gets wind of its power and decides to either use it for his own gain or sell it to the highest bidder. The Fellowship, in turn, has to track it down in this strange new world full of pirates, sea monsters, and cursed treasures.
Definitely Legolas and Will Turner. Legolas with his amazing archery skills could teach Will some new techniques, and Will could show Legolas the ropes of being a pirate. They both have a sense of honor and loyalty, so they would make an interesting duo.
The 'Crossing the Bar' may also be related to the theme of mortality. In pirate lore, the sea can be a very unforgiving place. Crossing a certain 'bar' could be seen as a step closer to death or a test of one's mortality. It could be a moment where the characters are forced to confront their own mortality and the fragility of their pirate lives.
Well, there are potc fanfictions that center around Davy Jones' backstory in more detail. Maybe showing his life before he became the feared sea creature. Some fanfictions also create new characters and their interactions with the existing ones. For example, a new pirate who challenges Jack Sparrow's status. And there are those that rewrite the ending of the movies, giving a different fate to the main characters.
Well, for potc fanfic, you could write about a new crew member joining Jack Sparrow's ship. This new character could have a special power, like being able to control the wind. They could use this power to help the ship escape from dangerous situations. Also, a fanfic about the origin of the Black Pearl would be cool. It could be that the ship was built from a cursed forest, and that's why it has some strange powers. Or you could write a fanfic where Davy Jones and Jack Sparrow team up against a new common enemy, like a powerful sea witch who wants to rule the ocean.
The 'A Study in Scarlet' PotC fanfic could blend the detective elements of the first story with the adventure and swashbuckling of PotC. It might have familiar faces from both in unexpected situations, making for an exciting read.
Blackbeard would probably be very interested in the magic in the Fairy Tail world. He might try to steal some of the powerful magic items or learn magic for himself. He could see the mages as a threat to his plans if they oppose him, but also as potential allies if he can manipulate them. He would likely use his cunning and power - hungry nature to his advantage in this new world.
Blackbeard was a fearsome pirate. One story is that he would tie lit fuses to his long, black beard before battle. The smoking fuses made him look like a devil from hell. This intimidated his enemies greatly. His real name was Edward Teach. He sailed the Caribbean, plundering ships and amassing great wealth. His ship, the Queen Anne's Revenge, was a symbol of his power on the high seas.