I was thinking of this update the other day. I do it sometimes. ;D Oh and B-sticking killed me today! D:
EDIT: Hey, EB360, I tried to compile some stuff for the yo-yo. This is just Ness' up smash, though. I'd think his down smash really makes no difference since it's still his yo-yo. Anyway here is a list of things.
Yo-yo + Fireball = Canceled Fireball
Yo-yo + Turnip = Canceled Turnip
Yo-yo + Banana = Canceled Yo-yo (The banana goes through causing Ness to slip)
Yo-yo + Peanut = Canceled Peanut (May drop peanuts for health)
Yo-yo + Egg = Canceled Egg
Yo-yo + Egg Roll = Canceled Egg Roll
Yo-yo + Arrow = Canceled Arrow
Yo-yo + Bombs = Canceled Yo-yo (Ness takes damage)
Yo-yo + Boomerang = Canceled Boomerang
Yo-yo + Needles = Canceled Yo-yo
Yo-yo + Homing Missile = Canceled Homing Missile (Must be timed correctly)
Yo-yo + Super Missile = Canceled Super Missile (Must be timed correctly)
Yo-yo + Charged Shot = Canceled Yo-yo
Yo-yo + Bombs = Canceled Bombs
Yo-yo + Laser = Canceled Yo-yo
Yo-yo + Gyro = Canceled Gyro
Yo-yo + Final Cutter = Canceled Yo-yo (From behind, the yo-yo cancels Final Cutter)
Yo-yo + Mach Tornado = Canceled Mach Tornado (Sometimes cancels the yo-yo)
Yo-yo + Sword Drill = Canceled Yo-yo/Sword Drill (It might depend on who brought out the attack first)
Yo-yo + Waddle Dee/Doo = Canceled Waddle Dee/Doo
Yo-yo + Pikmin = Canceled Pikmin
Yo-yo + Thunder Jolt = Canceled Thunder Jolt
Yo-yo + Shell Roll = Canceled Shell Roll (This causes Squirtle to go the other direction)
Yo-yo + Razor Leaf = Cancelled Razor Leaf
Yo-yo + Aura Sphere = Canceled Aura Sphere (The higher percent Lucario has, the harder it is to cancel)
Yo-yo + Rollout = Canceled Rollout
Yo-yo + PK Thunder = Canceled PK Thunder (This obviously needs to be timed)
Yo-yo + PK Jibaku = Canceled ?
Yo-yo + PK Fire = Canceled PK Fire
Yo-yo + Yo-yo = Nothing (One yo-yo is knocked back and the other makes a full circle)
Yo-yo + Psy Burst = Anything goes (If the yo-yo hits Lucas first, he takes damage. If the yo-yo is near Lucas but doesn't hit him, Ness may possibly take damage)
Yo-yo + Sausage/Fish = Canceled Sausage/Fish
Yo-yo + Pump = Canceled Pump
Yo-yo + Manhole = Canceled Manhole
Yo-yo + Grenade = Anything (The yo-yo goes a full circle and the Grenade falls back slightly)
Yo-yo + Nikita = Canceled Nikita (The missile from the Nikita flies upward. This requires timing)
Yo-yo + Air Spin = Canceled Air Spin (This requires perfect timing. You're better off using another attack)
EDIT: Hey, EB360, I tried to compile some stuff for the yo-yo. This is just Ness' up smash, though. I'd think his down smash really makes no difference since it's still his yo-yo. Anyway here is a list of things.
Yo-yo + Fireball = Canceled Fireball
Yo-yo + Turnip = Canceled Turnip
Yo-yo + Banana = Canceled Yo-yo (The banana goes through causing Ness to slip)
Yo-yo + Peanut = Canceled Peanut (May drop peanuts for health)
Yo-yo + Egg = Canceled Egg
Yo-yo + Egg Roll = Canceled Egg Roll
Yo-yo + Arrow = Canceled Arrow
Yo-yo + Bombs = Canceled Yo-yo (Ness takes damage)
Yo-yo + Boomerang = Canceled Boomerang
Yo-yo + Needles = Canceled Yo-yo
Yo-yo + Homing Missile = Canceled Homing Missile (Must be timed correctly)
Yo-yo + Super Missile = Canceled Super Missile (Must be timed correctly)
Yo-yo + Charged Shot = Canceled Yo-yo
Yo-yo + Bombs = Canceled Bombs
Yo-yo + Laser = Canceled Yo-yo
Yo-yo + Gyro = Canceled Gyro
Yo-yo + Final Cutter = Canceled Yo-yo (From behind, the yo-yo cancels Final Cutter)
Yo-yo + Mach Tornado = Canceled Mach Tornado (Sometimes cancels the yo-yo)
Yo-yo + Sword Drill = Canceled Yo-yo/Sword Drill (It might depend on who brought out the attack first)
Yo-yo + Waddle Dee/Doo = Canceled Waddle Dee/Doo
Yo-yo + Pikmin = Canceled Pikmin
Yo-yo + Thunder Jolt = Canceled Thunder Jolt
Yo-yo + Shell Roll = Canceled Shell Roll (This causes Squirtle to go the other direction)
Yo-yo + Razor Leaf = Cancelled Razor Leaf
Yo-yo + Aura Sphere = Canceled Aura Sphere (The higher percent Lucario has, the harder it is to cancel)
Yo-yo + Rollout = Canceled Rollout
Yo-yo + PK Thunder = Canceled PK Thunder (This obviously needs to be timed)
Yo-yo + PK Jibaku = Canceled ?
Yo-yo + PK Fire = Canceled PK Fire
Yo-yo + Yo-yo = Nothing (One yo-yo is knocked back and the other makes a full circle)
Yo-yo + Psy Burst = Anything goes (If the yo-yo hits Lucas first, he takes damage. If the yo-yo is near Lucas but doesn't hit him, Ness may possibly take damage)
Yo-yo + Sausage/Fish = Canceled Sausage/Fish
Yo-yo + Pump = Canceled Pump
Yo-yo + Manhole = Canceled Manhole
Yo-yo + Grenade = Anything (The yo-yo goes a full circle and the Grenade falls back slightly)
Yo-yo + Nikita = Canceled Nikita (The missile from the Nikita flies upward. This requires timing)
Yo-yo + Air Spin = Canceled Air Spin (This requires perfect timing. You're better off using another attack)