Well, I may as well give it a go.
KOS-MOS: She was built to fight Gnosis, monsters, so she's combat-savvy as well as being equipped with several different weapons including, but not limited to: A blade-arm, a gun-arm, a drill arm, a hammer-arm and a scythe. All of her weapons are stored in a remote location that teleport to her for use, allowing her to use all of her arsenal however she needs to.
B: R-CANNON: An arm-cannon blast, aimable in all eight-compass directions. Chargable. (charging increases power, range)
Forward B: R-DRILL: A rushing drill-arm attack. Chargable. (charging increases power, distance, hits)
Up B: Dragon Tooth: A vertical sweeping blade slash, launches enemies into the air. Chargable only on the ground. (charging increases power, vertical distance)
Down B: R-HAMMER: A hammer-arm smash, capable of burying enemies if charged. Chargable. (charging increases power, adds pitfall effect + breaks shields if fully charge)
Final Smash: X-BUSTER: A spreading laser that sweeps forward across the stage.
Neutral Attack: Punch, Particle spread
Dash Attack: Baseball slide
Forward Tilt: R-BLADE sweep
Up Tilt: High kick
Down Tilt: Leg sweep
Forward Smash: R-BLADE: An vertical slash with a sword-arm.
Up Smash: F-SCYTHE: An arcing-upwards swing with a scythe. (hits in front then overhead)
Down Smash: A strong punch downwards.
Neutral Air: Twirl: A regular mid-air spin attack.
Forward Air: Heel Kick: A heel kick. (meteor smash)
Back Air: Spinning Heel Kick: A heel kick in the opposite direction. (meteor smash, turns KOS-MOS around)
Up Air: S-SAULT: An aerial backflip kick.
Down Air: Drill Kick: A spinning, drilling kick.
Forward Throw: F-GSHOT: Pushes the enemy into the air them shoots at them with a gatling-gun.
Back Throw: Shoves the enemy back with her right elbow the shoots them with R-CANNON.
Up Throw: D-S-SAULT: Backflip kicks the enemy over her head then kicks them again.
Down Throw: Throws the enemy on the ground then stomps on their back.
Up Taunt: KOS-MOS does her Ether casting animation from Ep.1
Side Taunt: KOS-MOS reaches forward with her right arm and her eyes flash blue briefly.
Down Taunt: KOS-MOS activates the Hilbert Effect (is just for show here)
Victory 1: Xenosaga Ep.1 victory pose
Victory 2: Xenosaga Ep.2 victory pose
Victory 3: Xenosaga Ep.3 victory pose
Colors:
Blue - Default
Red - Reference to the Realians in Ep.1
Green - Reference to Aschen from SRW: Endless Frontier?
Black - Reference to T-elos
Brown - Reference to the prototype KOS-MOS
Alternate Costume - Ep.3 armor