One of my issue is exactly that. Fighters, fictional and real, will share at least one move. Just look at say, Muay Thai and Boxing. Both have jabs and straights. Does that mean a Muay Thai fighter and Boxer are clones of each other? Hell no.
Take Baek Doo San and Hwoarang from Tekken. Both are Taekwondo fighters and Hwoarang's a student of Baek. They fight similarly, but have different play styles and their own unique flair. Baek is an old school fighter who uses more hand techniques than Hwoarang. Also, he doesn't switch his stance. Baek seems more straightforward and traditional. Hwoarang fights more deceptively and uses kicks almost all the time with little punches. Plus, he has a bit more flashy moves. One martial arts style, two fighters, and two different approaches to fighting.
Tons of characters in Super Smash Bros. share the flying side kick. Fox does it for dash attacks, Link has it for a nair, Zelda has it for a fair, Sheik has a modified one for a nair, Luigi has one for a nair, etc - it's been a long time, so I don't remember all of them. Does that mean all of them are clones? No. Wolf's smashes and normals are mostly different compared to Fox and Falco, but he shares similar specials. I mean, what the hell is he going to do? He's from the same universe, with the same technology, but using variants, and fights with his claws and feet instead of his fists, tail, and feet like Fox or feather-fists, feet, beak, and tail like Falco. Now, if we were talking about Krystal who's first appearance involved using a staff that could fire fireballs, spray ice, launch the user, create shields, and create quakes, then that would be totally unacceptable if she was basically a female Fox.
There's only so much you can do with a sword. What's a swordsman gonna do besides swing vertically, diagonally, horizontally, and stab with the sword? He could add martial arts, perform flourishes, or if he's lucky send out sword beams. Luckily, Link has his items, Marth fights like a fencer, Ike has a magical flaming sword and fights like a brawler, and Shulk's sword has laser beam-thingies - never played Xenoblade Chronicles so I don't really know.