Hmm, lets see. Been labbing Joker a lot today so off the top of my head and using SSBWiki to compare Joker and Sword. Also, I'm going with normal Joker and not Arsene (with one exception):
Two disclaimers are neccessary: I might be mistaken here on several fronts, since I don't have all characters in my head's database, but still. Also, I'm doing this without knowing from any datamine, so any raw data could null my guesses.
Jab attacks: Most similar to Mii Swordfighter. Replaces Sword's Upward (which is third and last) stab with a backhander, and the backhander comes second.
F-tilt: Joker's reminds me some of Snake's, being a double hitter. Sword's is decently similar to Link's.
U-tilt: Robin's, maybe. Animation's somewhat different between the two. Sword's similar to Link's again.
D-tilt: Cloud, being a slide and all. Sword's D-tilt is similar to Marth's.
Dash attack: Running version of Zero Suit's F-Smash kinda. Sword's a slide and a outward swipe.
F-Smash: I could see the similarity between Joker and Sword, but SSBWiki points out that Joker's is similar to Falco. Joker doesn't swing inwards while Sword does.
U-Smash: Another tough one, but Ryu's uppercut with a knife, maybe? Sword's a two-slash and jump, rather similar to Link's again.
D-Smash: There are tons of sweeping in front and behind. Joker and Sword do this, but so do Mario, Link, Marth, Rosalina... yeah. Inconclusice I'd say.
Nair: Joker and Sword both do corkscrews. The thing is, corkscrews are also ridicoulsly common. Even Bowser does it nowadays! Everything is truly better with spinning.
Fair: Joker does "A hook kick, followed by a roundhouse kick." Zero Suit does the exact same thing. Sword meanwhile stabs forward three times.
Bair: Joker does an upward swipe here. I'm gonna hazard a really wild guess here, but perhaps a upward version of Cloud's? Sword spins before doing his backward slash. Cloud "merely" turns around. This is a vague case, could be most similar to Sword but I'll not push any definitive judgement here.
Uair: Joker's borrowing from Sheik here. Sword spins here again.
Dair: Joker clearly recorded Marth's infamous downair. Sword's reminds me of Corrin's.
Grab: Both Joker and Sword reach out with one hand. The thing is, it's really common. Pass.
Pummel: Both Joker and Sword knees the victim. Not sure if this is as common as the grab though, but Captain Falcon's the progenitor of this.
F-throw: Now we're getting into different territory. Joker does a forward toss, Sword kicks the victim.
B-throw: Joker does Marth's b-throw. Sword roundhouse kicks.
U-throw: Joker throws directly upwards, kinda like (Dr.) Mario's. Sword thinks just tossing is for wimps and follows up with a midair spinning slash. Told ya spinning makes everything better.
D-throw: Both Joker and Sword slam the opponent off the ground. Joker, however, adds some flourish to it all too. Before we rush into any conclusions, it's kinda common since characters like Palutena, K. Rool and Lucas do this too.
Floor attacks (front, back, trip): Passing on this one too. Swinging back-and-forth's pretty damn common when rising up.
Edge attack: Joker's reminds me of Cloud's, being a slash, while Sword stabs akin to Link.
Specials: Hoo boy now we're getting complicated, since the Mii's have three different choices for their Specials:
B: Joker's Gun seems like the lovechild of Falco's and Bayonetta's. Falco's due to the animation while normally shooting, Bayo's because Joker can pull off similar gun stunts. Sword has the tornado, the shuriken or multi-hit stabs as choices here.
Side B: Joker's Eiha is a variant of Robin's Arc Fire in how it travels, with extra poison. Sword has the spinning charge, charged multi-stab and the chakram.
Up B: Joker's Grappling hook is a tether and upward version of Isabelle's rod. Sword has a sword version of Brawler's "Rise up, crash down", a series of sword strikes dashing in a straight line (which can be angled), and Link's Spin as choices.
Down B: Joker's Rebel's Guard reminds me of Incineroar's Revenge, only combined an expanded version of Cloud's limit mechanic. Here I'll make the exception since Arsene gives Joker a version of Palutena's counter - reflecting both melee and ranged attacks. Sword has a counter here too, true, but it works more like Marth's. The other Down Bs are a slash working like Mario's Cape and a dash forward similar to Falcon's / Ganon's but with a sword.
TL:DR:
I could see similarities in 4 or so moves between Joker and Sword - the thing is, the eyetest doesn't really work when a lot of the similar attacks are common with the cast (corkscrewing Nairs and one handed grabs). Given that disclaimer, other characters Joker appears to have borrowed from are Marth, Zero Suit and surprisingly enough Falco. Meanwhile, Sword shares some stuff with Link, and looks decently similar to Toon Link.