I'm pretty content with this ordering. Pikachu, Mario and Yoshi could be higher, Falcon could be a bit lower, but I think this is good.
Ness - Extremely solid moveset. Dash attack and fair have insane range. bair, uair, bthrow are all extremely good killing moves. nair comes out fast and hits fairly hard, and is a solid OoS option. PK Fire and dthrow confirm into a bunch of stuff. PK Thunder is an excellent harassing tool and an amazing projectile, and PK Thunder 2 kills at like 40%. One grab at 70-80% could mean death, and if you're above 110% you are definitely dead.
Luigi - dthrow combos all day erry day, whether it's for racking up damage or killing. Also has some of the best frame data in the game. Recovery is really good if you master the art of mash hard. Fireballs are a really great projectile. Fast killing moves in Up B, smash attacks, and dthrow -> Cyclone.
Sonic - Being the fastest character in the game is really good. Having kill moves on top of that is even better. Sonic has the ability to outcamp most characters even without a decent projectile due to his hit-and-run nature.
Zero Suit Samus - Confirms into Flip Jump 40% spikes, amazing recovery with Flip Jump and Plasma Whip, hits hard, hits fast, throw combos are really great but her grab is somewhat lacking. Paralyzer is an amazing tool. Boost Kick is an excellent killing move.
Fox - Hits fast, hits hard. usmash still kills at dumb percents and still has confirms such as weak nair. Recovery is great thanks to being able to use Fire Fox after Illusion. Blaster is a pretty good projectile to force the approach. Jab lock.
Pikachu - Extremely fast. Quick Attack is one of the best moves in the game imo. Frame 1 Thunder GTFO is decent, Thunder Jolt is a reliable projectile, throw combos into Thunder kills are good, smashes are good, has a lot of safe aerials due to the reduction of hurtboxes. Edgeguarding is good due to lasting hitboxes and amazing recovery.
Captain Falcon - Dumb range on stuff like fsmash, dash attack, and dash grab. Lots of confirms off of grab, knee is a super powerful finisher and can be set up into. Overall extremely strong moves. Raptor Boost now killing is dumb. Disadvantage state is pretty bad though, and recovery isn't too great.
Mario - Amazing frame data and great combos. A very solid character, not really much I can say. Very basic though, so not higher.
Diddy Kong - Nerfed to oblivion but still solid. uthrow still combos into stuff, banana is really good, Monkey Flip is a great move. Fast aerials with great range.
Yoshi - No one uses this character but everyone hates him. Amazing frame data and power, high maneuverability, heavy, command grab leading into free damage, a very good projectile. Why isn't this character placing higher?