Just looking at this and slowing it down there's so much to work with.
Neutral special: The ball of water, she creates the ball in front of her and it'll stay there almost like villagers tree, pressing neutral special again makes her do that same swing, destroying it and making it explode, maybe opponents could get caught in it or something?
Side special: Her strong attack, kinda works like Ike's, you charge up and then zoom forwards.
Up special: The last hit of her regular combo, the jumping piledriver move, kinda works like dedede's.
Down special: The raining kunai move, if used on the ground she'll jump up first before spawning them, they then fall around her.
The sliding move in her regular combo could be a good dash attack. The jumping and swinging the sword with her feet move in her normal combo could be her forward smash. he last combo with the water swords could be her down smash. Her neutral air could be her aerial strong attack, the somersault one. Her up/forward air could be her regular aerial attack where she spins up.
I'd like her Strong Attack (X) to become her dash attack. Her second Y+X combo, where she does a back flip using her weight to bring down the Giant Blade in front of her (whilst facing backwards herself) makes for a good F Tilt or F Smash.
The piledriver move? You mean that swirling aerial attack of hers? That would work well indeed! I thought of it as a N Air, but that Up B could work to and makes her a little different from Ike and Cloud indeed.
D Air is also easy to pull from Hyrule Warriors, it's her last combo attack, I think it's a strong attack where she pillars down the Giant Blade into the ground, making a sort of shockwave.
U Tilt could be that one kick of her victory animation, kind of similar to Ganondorf's current U Smash, but obviously faster and far less powerful. Sends her foes up straight upwards.
D Tilt could be the slide she finishes her regular combos with. This is kinda what Cloud also does however... Shouldn't really be all that much of a problem right?
AAA is what I said the regular YYY attack, with a rather strong finisher.
U Air is her strong attack in the air, not the Aether-like attack but how she swoops her sword upwards. Kinda only is one move in her move set in HW that does this.
D Smash could be where she slashes the ground, and make a burst of water come out of it, having prety good vertical knockback. It's her Weak Point Smash attack basically.
F Smash could be somewhat like Link's, where she does a double attack by first hitting opponents with her sword lightly, then follow up with a jumping attack where she attaches her sword to her feet. Second attack would be more powerful, and is rather fast as well but has some lag afterwards.
U Smash is where she swings her sword overhead, like she does with her Special attack (pressing A).
General stats:
Weight: Marth/ Lucina's
Running speed: Sheik's
Fall speed: Ike's
Air speed: Zero Suit Samus's
Traction: Cloud's
Air acceleration: Luigi's
Kinda think a moveset writes it's own here. Really not much which can go wrong.
And for the haters who keep on claiming there's no spin-off based moves in the game, Mega Man uses that one uppercut that was from a crossover game, so there's that. Am not knowledgable about Mega Man otherwise, so that's the only info I got about it. Besides, Hyrule Warriors did great on all systems, and is STILL doing great.