Swashbuckling is more an attitude than any particular lifepaths or skills beyond some weaponry and perhaps a dash of Ropes-Wise for swinging from likely dangling things. (I’m half kidding, but only half! Wises can do a lot. Acrobatic Feats-Wise, Flashy Distraction-Wise, and many more can make for exciting feats.) If you’re looking for high seas, the Seafaring lifepaths are great, of course. Just about anything works for court.
Allow characters to go big and bold with their over the top actions without giving them very high obstacles. The game you’re aiming for should have them leaping from balconies with rapiers and cutting the captive’s bonds with an arrow far more often than a grittier game! The big thing is for your players to grasp what level of action is possible and encouraged. “I jump up onto the table and kick the soup turreen into the viscount’s face as a distraction!” Sure, roll Speed! “I don’t just want to disarm him, I went to send his rapier sailing into my companion’s hands!” Not covered by the disarming rules as written, but assign it an Ob and go for it. “I want to throw my sword so it cuts the hangman’s noose just as my love begins his fatal plunge!” In another game that might be laughed down as completely ridiculous. In this one? Throwing, make it tough, and get 'em to spend artha on it. You set the feel of the campaign by the Intents/Tasks you allow and the Obs you set. Be generous with the stuff that sets the tone you want.
Remember, any time characters do something just to be stylish you Say Yes. Looking cool is all part of the genre. When they try something stylish and with serious repercussions for failure, never make the consequence of failure screwing up the cool part. If you want to swing from ship to ship and botch your roll you don’t miss your grab and face-plant on the deck or get stuck dangling in the middle or slip and fall half-way through your swing. Instead, you don’t quite time your swing right and end up right in the center of the biggest cluster of grinning pirates, or the rope snaps and now you’re stranded (or both!). If a character is to be dashing, heroic swordsmen and you resolve combat with one roll, failure isn’t defeat. It’s not breaking free of the guards in time to catch the fleeing carriage, or taking a wound in the process, or having your mask damaged and your secret identity compromised. Success is relatively easy; getting failure to really sting while still leaving characters looking awesome is tricky business. In a game with as much failure as BW, and everyone will fail often, you need to make sure failure is still immense fun as well as increasing pressure.
You might also want to go hard on Steel tests inflicted by PCs (they inflict shock, awe, and astonishment with their daring exploits!) but light on Steel tests that they have to make (they laugh in the face of danger!); while there are traits that support this, you can just build it into the game as an assumption. Call for fewer of them, reduce Obs, or otherwise allow them to freeze less and laugh in the face of danger more. This is hard to calibrate until you’ve got some experience with how Steel works and how you want it to work. Steel itself is Rim (kind of optional) and you may just find it largely inappropriate for the style you’re going for. Or it may be important that your characters freeze and hesitate and flee just as much as anyone else; after all, bravery isn’t not being afraid, it’s working through your fear and acting anyway.
Fight can make the staple swashbuckling duel into a beautiful, uncertain, tense drama the way most games’ “I swing at you, you swing at me, I swing at you” dynamics don’t. Don’t be afraid to have trait votes that give bonus dice or even reduce Obs for characters’ schticks. If one character is always spouting clever one-liners while performing martial feats, a trait that allows FoRKing in Quip-Wise when the player comes up with a snappy witticism will keep them coming. If another character is always swinging on ropes, vines, and chains, a trait that gives bonuses to combat rolls while doing so would be nice. Make it clear from the outset that you want to see these things, and encourage inventing traits for trait votes that codify them, and you’ll get all kinds of crazy antics. Duel of Wits does the same for