Here's my vision of Luigi:
B: Fireball (Of course!)
Side B: Green Missile (Yep)
Up B: Spring Jump (same as Mario)
Down B: Polutergust 3000 (He can just blow away people, like Mario's FLUDD attack, or he can suck them in and blow them away, like King Dedede's Inhale attack)
Final Smash: Fireball Tornado - Luigi throws some green fire balls out, and they form into a fire tornado, hitting and sucking in anyone in its path!
Here's my vision of Captain Falcon:
His attacks: same
Final Smash: Blue Falcon - Captain Falcon gets inside his F-Zero machine, and from one side, rams through the stage. Back at the side he started, his Final Smash is done.
Here's my vision of Bowser Jr.: (if he gets in the game)
B: Fire Breath (like Bowser)
Side B: Koopa Illusion (with rainbow paint colors, he rushes through like Fox)
Up B: Paint Brush Copter (with his paint brush, he uses it to create colors above him. With those colors, he sails away, sort of like Peach and her parasol)
Down B: Meteor Drill (with his paint brush, he drills down in a cyclone)
Final Smash: Shadow Mario Runaway (with his paint brush, he gets a golden ball from the smash ball and turns into Shadow Mario. He turns invincible and can harm anyone he touches)
Here's my version of Pichu: (if he comes back)
B: Thunder Jolt
Side B: Zap Cannon (he shoots a zap cannon at his enemies)
Up B: Agility/ Quick Attack
Down B: Charge (he charges himself as much as he needs to. Next time he does one electric special move, it'll cause some harsh damage)
Final Smash: Super Thunder (he charges himself so much. When he presses B, a huge Thunder will come down the stage. However, he'll get 50% damage.)
And that's it.
