Yo, you don't have to short hop cutter dash anymore.
Also C4 is the thing he sticks on you, mines are the ones he puts on the ground.
Wario is a interesting matchup that I'm working on with my friend. I'll hopefully come back in a few days or whatever and let you know. Just saying if he's a Wario that likes to abuse the side-B/dash grab mixup (his side-b and dashgrab look the same; if you shield it expecting side-b and it ends up being the dash grab you'll get grabbed), you can inhale him out of it. Also rocking in the air when he tries to follow-up can ruin a lot of his stuff. He also kills stupid early so I would recommend banning Warioware (lol) and something like Yoshi Story or Fountain. I like to push for Dreamland for that matchup. Get him offstage, and if he has his fart, get him low enough to where he has to use it to recover. Get back onstage, and wait for the fart. After he does it, go down and dair or nair or bair him, and continue to aerial him away. Also if you wait for the fart you can jump out, inhale him, drop a bit and spit him out. Without the fart his recovery is garbage and he won't recover. Dreamland is good for this. Also like all characters dthrow --> techchase is great. I'll explain the options of that later.
For Ness you can literally spit him under the stage and it wrecks him. Spit him under the stage, fair/nair/uair (not sure which works better) him out of his double jump, and grab ledge. His recovery will pretty much never make it.
Samus is an interesting matchup, especially if she's missile-heavy. If Samus plays it right and just camps you hardcore you can get wrecked. You can't even guarantee duck under her missiles if she jumps and shoots them at the right time. If you do get in though, dthrow is wonderful. Different from other characters, where it leads to the techchase, on floaties like Samus, it can lead to all sorts of things, as it puts them in the air in front of Kirby. You can get an utilt from it at low percents (utilt utilt bair), you can get a short hop inhale from it for the lulz, and you can even get an usmash from it. I'm not sure what percents the usmash work, but I can tell you that it does stop working somewhere around the early hundreds (i might be wrong tho, have to test). Either way, dthrow to usmash is great against Samus. You'll have to do some DI following, but it's not hard. Just avoid stages like Dreamland and push for the lower ceilings. Hell, take her to Fountain (melee Samus favorite stage) if you feel ballsy enough. Don't try to follow up on her if you hit her far away from you, even if it looks like you might get something. She'll nair or Ice Fair you. Melee players trying to combo Samus know this well. Melee Nair got out combos that it seemingly shouldn't have been able to. It carries over.
Charizard is also interesting. He's hard to kill both on the sides and on the bottom. Dthrow techchase is great. You can react to what he does. If he techs through you, you can regrab. If he techs straight up you can regrab. If he doesn't tech you can jab reset regrab. If he techs away, you can dash attack into utilts and now he's in the air. If you PREDICT a tech away, you can head that way early and regrab. If you PREDICT a netural tech or no tech, you can get a hammer. Make sure you react fast enough to the neutral tech so he doesn't spotdodge your grab. If you find that you miss it a lot and he dodges it a lot, to the point where he does it automatically, either wait a second for the grab or hammer. When Charizard is in the air, avoid just running at him (unless he's in hitstun). Zard's nair and side-B (the sneeze) can beat most of what you can do. Wait for him to do something then react. If he's ever gliding at you, don't run in. He'll do glide attack and it'll beat you. Make it seem like youre going to attack, wavedash back to avoid the glideattack, and hammer. If he ever launches you up, use Rock. He can uair you for days into an upB for an early kill. Unless you rock through him. It messes up a lot of his stuff. Stage choice is a gamble. If you feel you can just live for awhile against a beast like Zard and kill him normally before he kills you, take him to a tiny stage like Yoshi Story or (god forbid) Warioware. If you think you can gimp him (pretty hard to do against Zard), take him to Dreamland. I prefer the latter, as our killing options just don't cut it against a Charizard. Gimping him is hard, but if you bair him away for long enough, then hang out onstage and dsmash whatever he tries to do, you can get him. Inhale off the stage just works too. Just make sure he's someone who tries to mash out (or you'll both die) and make sure it's a stage with a large bottom (or you'll both die). IF he doesn't mash out, spit him out and return to the ledge with a few well-timed bairs to keep him away.