Ok, my speculation/wishes:
Gimmick: Persona change. Joker can use Shield+b (as inklings) to change Personas. He has 5 in total: Arsene, Jack Frost, Thor, Pixie and Jack o Lantern.
Jab: Small dagger swings directly in front of Joker.
Neutral Infinite: Lot of quick dagger swings in front of Joker, ends with a gun shot.
F-tilt: Wide dagger swing in front of Joker.
U-tilt: Upwards swing with Joker's gun, shoots small knockback bullets in a diagonal angle, only if you keep the button pressed.
D-tilt: Slide through the ground in style. Can do a full jump/short hop out of the animation whenever.
N-air: Two quick dagger swings in front of him, in a slight downwards diagonal angle.
F-air: Bullet shot in front of him, travels small distance.
B-air: Backwards kick, one hit.
U-air: Wide dagger swing over him.
D-air: Plunges to the ground looking cool (Joker), can be comboed into D-tilt.
F-Smash: Uses current persona to do a wide attack in front of him. Can have a darkness (Eiha), Ice (Bufu), Electric (Zio), Wind (Garu) or Fire (Agi) effect, depending on the Persona.
D-Smash: Slashes the floor with the dagger in front and behind him. If catches people at the ledge it can spike.
U-Smash: Fires gun directly above him.
Grab-jab: Opponent gets punched by the current persona while Joker holds the opponent with one hand and his gun pointing at him.
D-Throw: Slams opponent against the ground in front of him.
F-Throw: Jumps from opponents chest, moving backwards and throwing his opponent forwards. High knockback.
B-Throw: Jumps over opponent's shoulders, moving Joker forwards and throwing his opponent backwards. High knockback.
U-Throw: Throws opponent above him and fires his gun upwards.
Specials:
Neutral B:
Sends small projectile in front of him, with a different attribute depending on persona equipped.
- Arsene: Eiha. Sends shadows directly forwards, mid-range from where Joker is. Multi-hit and small knockback.
- Jack Frost: Bufu. Sends ice shards directly forwards, short-range from where Joker is. One hit and small knockback, with a chance of freezing at high %.
- Thor: Zio. Sends a lighting bolt directly forwards with a slight upwards angle. Quite quick travel speed and long-range from where Joker is. Small knockback.
- Pixie: Garu. Sends waves of air directly forwards that also cover the ground level. Long range and multi-hit when it connects.
- Jack o Lantern: Agi. Detonates a small explosion short-range in front of Joker. High knockback.
Down B:
Buffs Joker for a small amount of time. Needs to be charged similar to Wii Fit Trainer's Down B.
- Arsene / Jack Frost: Rakukaja. Increases defense, lowering knockback received for a while.
- Thor / Jack o Lantern: Tarukaja. Increases attack, increasing knockback dealt for a while.
- Pixie: Sukukaja. Increases movement speed and jump height very slightly for a while.
Up B:
Wings of Rebellion: Sends Joker flying upwards. Effect/distance varies depending on Persona equipped.
- Arsene: Arsene appears behind Joker and flies upwards with him. Regular distance with a wide hitbox above Joker (Think Mario's Up-B on distance/angle)
- Jack Frost: Jack frost appears below Joker and creates a "step" with both hands interlocked (don't know how to explain this in English...), having Joker jump from it and sending him directly upwards with small ice particle effects surrounding him. Small hitbox all around Joker, but can be broken with a strong attack. (Think Kirby's Up-B on upwards trajectory)
- Thor: Thor appears behind Joker and swings his hammer upwards, allowing Joker to raise with him. (Think Simon's Up-B on distance/angle/power, but with an electric effect)
- Pixie: Pixie appears behind Joker and creates gusts of wind that sends him flying upwards. No hitbox whatsoever, except for the landing and first frames of the gusts of wind. (Think Inkling's Up-B in terms of distance).
- Jack o Lantern: Jack o Lantern appears behind Joker and creates an explosion below him, sending Joker flying slightly upwards (Think Dr. Mario's Up-B on distance/angle). Has no hitbox above Joker, but the explosion can spike opponents on the first few frames.
Side B:
Ambush. Joker leaps forwards. If it catches people, he stands atop their shoulders and can do one of the following actions:
Attack - A button. Small jabs.
Throw - Forward or Backward stick movement: Similar to F-throw or D-throw, but with small knockback.
Disable - B button. Knocks on the head with the gun, trips opponent and makes Joker do a short hop upwards and backwards.
If nothing is pressed or the opponent mashes out of the movement, the "release grab" animation is played.
Final Smash: All Out Attack. All characters on the screen trip and Joker has a few seconds to hit as many as he can with attacks. After these few seconds, whomever he hit goes into the "All Out Attack" screen, where Joker and all his party members (except Futaba, ofc) raid on the opponents. Does around 40% damage, although small horizontal knockback. If the enemie/s are over 100% damage when the attack ends, they are insta-killed (Think Zelda's FS) and one of the "all out attack" screens form any of the party members appears.
Whoo! Sorry for the long post. If anyone can share with me the "Spoiler" code I'd be grateful, I'm still kinda new here :D