Hey there, I'm here to join the Bandana Brigade, as well as offer my own moveset idea for our favorite Player 4.
The general concept for the character is walling out approaches with various mid-range tactics and quick up close tactics. Bandana Dee utilizes his spear and his special blue parasol extensively. Similarly to how quickly Pit uses his blades and bow, Bandana Dee quickly transitions between the two during moves that use them, and the last move he used reflects in his idle animations. I decided against utilizing Beam in any way because that belongs to Waddle Doo and feels disingenuous to Bandana Dee's skillset. Additionally, other than his copter spin, I feel his spear attacks should be exclusively stabbing, other than Spear Copter I feel like him swinging it doesn't make sense.
Bandana Waddle Dee
Stats
Ground Speed: Equal to Kirby
Air Speed: Almost as good as Jigglypuff
Weight: A bit heavier than Kirby
Jumps: Ground Jump + 4 Midair Jumos
Wall Jump/Cling: No
Crawl: No
Animations
Entrance Animation: Crash lands on a Warp Star (from the opposite direction Kirby comes in from) and spins around dizzy before pulling out his spear.
Taunts & Victory Animations: The Reddit link above honestly covers this better than I could, those are all quite good.
Defeat Animation: Claps in a way that resembles his animation in the bleachers of the Masked Dedede fight.
Normals
Jab: Single Spear Thrust, slow startup but the best range of any Jab, decent for walling out approaches, slight sweetspot at tip. (5% or 7%, low nearly horizontal KB)
Jab Infinite: Multispear Attack, entered from chaining off of regular Jab or by holding attack for Infinite Jab. Good range and finishes off with a stab. (3%, nearly horizontal KB)
Forward Tilt: Parasol Swing, Bandana Dee quickly swaps out for his parasol and swings it forward, with a splash sourspot at the end extending the hitbox. Slow, but good for applying pressure and keeping slower characters away, and sourspot can lead into grab. (12% & diagonal KB at Parasol, 9% and flinch from water)
Down Tilt: Slide Kick, the move every Kirby character has for sliding across the ground, Pops enemies into the air. (4% & vertical KB)
Up Tilt: Skyward Thrust, quickly stabs upwards with his spear, range comparable to Marth's Up Smash and more speed, but with much less power or knockback. (8%, vertical KB)
Dash Attack: Parasol Drill, rushes forward with a multihit parasol attack that walls out approaches and negates projectiles. (10% if all hits connect, diagonal KB)
Aerials
Neutral Air: Pulls out his parasol and twirls it 360 degrees, hitting in front and behind, similar to Marth's Nair but at an angle similar to Ness' Nair. (8% & horizontal KB on forward hit, 7% & diagonal KB on back hit)
Forward Air: Stabs with his spear three times in very quick succession, similar to Ridley's Fair but with more range and slightly less damage, very low KB on final hit. (7%, minimal horizontal KB)
Back Air: Aerial Back Thrust, readies his spear before thrusting it behind him, similar to Shulk's Bair, sweetspot at tip for kills. (14% & high horizontal KB at sweetspot, 9% & minimal diagonal knockback at sourspot)
Down Air: Moon Drop, holds his spear downward and twirls downward at high speed, stall-and-fall, spikes on startup, guarnateed death if used offtstage. (14% and spike on startup, 8% and diagonal knockback during the rest of the move)
Up Air: Flip Kick, similar to Kirby's Uair but with a much more diagonal knockback angle to help lead into Fair or a few other moves. (6% and low diagonal KB)
Grab/Throws
Grab: Essentially similar to Kirby's.
Pummel: Essentially similar to Kirby's, slightly slower.
Forward Throw: Essentially similar to Kirby's, but with much more horizontal knockback and greater kill power. (12% and high horizontal KB)
Back Throw: Essentially similar to Kirby's but with much more horizontal knockback and greater kill power. (13% and high horizontal KB)
Down Throw: Uses Parasol Dive to drill into the opponent on the ground, combo throw. (9% and low diagonal KB)
Up Throw: Circus Throw, bounces opponent on top of his parasol for a bit before launching them, not good for killing or combos, just to get the opponent in the air and restrict their options. (10%, vertical KB)
Smash Attacks
Forward Smash: Bandana Dee charges up before stabbing forward with his spear with great force, range slightly less than Shulk's Fsmash, but single hit and with a sweetspot at the tip, can be angled. (14% uncharged sourspot, 19% uncharged sweetspot, 22% charged sourspot, 28% charged sweetspot, all high to extreme diagonal KB)
Down Smash: Bandana Dee charges up before doing a quick stab forward, followed by a Back Thrust, less range than Fsmash both ways and each hit has a slight sweetspot at the tip. (12% uncharged sourspot, 15% uncharged sweetspot, 19% charged sourspot, 23% charged sweetspot, all high nearly horizontal KB)
Up Smash: Bandana Dee readies his unopened Parasol before striking upwards and popping it open, hitting with moderate force. Very quick startup with a vacuum hitbox on startup that leads into the main hit, similarly to Marth's Usmash. Useful for when an opponent has gotten past your spacing tools. (14% uncharged, 20% charged, both nearly vertical KB)
Special Moves
Neutral Special - Gale Thrust: Bandana Dee charges in place, before driving forward a good distance with his spear pointed forward. Like Roy and Mac's Neutral Bs, it can be turned around before launching, or shield canceled. Damage depends on the level of charge and distance traveled, with a max-charge, close-range attack dealing the most damage and knockback. If used midair, this move can grant incredible horizontal recovery.
Side Special - Spear Throw: Bandana Dee chucks his trusty spear in an arc with moderately slow airspeed, an extremely good projectile for sniping offstage opponents. If done out of a dash, the spear is thrown faster, but with a lower arc. When used midair, it slightly stalls your fall, and the move can be used in succession about half as quickly as it can in the actual Kirby games. (Triple Spear is left out because it would honestly be pretty unreasonable as a projectile by Smash standards, imo) (9% and diagonal knockback)
Down Special - Parasol Shield: Bandana Dee ducks under the cover of his Parasol. All projectiles that hit the parasol are instantly negated, and it causes opponents that bump into it to take minor damage and flinch, which can lead into a grab. Very good against opponents who like to run in for grabs or try to crossup with turnaround grabs, but vulnerable to weapon-based attacks and with much more lag than just dropping shield, making it a riskier option with greater benefits in some situations.
Up Special - Spear Copter: Bandana Dee spins his spear around at high speed, taking flight. The move has slow startup before the hitbox comes out, making it fairly vulnerable. Once in flight, it creates a very wide, but very thin multihit hitbox over Bandana Dee's head that lasts a total of three seconds. Despite the incredible lift, Bandana Dee has horrible horizontal momentum in this state. To combat this, he can press Down to cancel the Spear Copter into Drift, wherin he quickly opens his Parasol and begins descending with his original airspeed. Drift has no hitbox, leaving him vulnerable on all sides, but can be an effective recovery mixup compared to the slow movement of Spear Copter. If Spear Copter is finished without being canceled, Bandana Dee goes into freefall.
Final Smash: Megaton Punch
After a quick pose, Bandana Dee does a leaping punch at the ground in front of him. Anyone within range suddenly finds themselves in Pop Star Colosseum, where Bandana Dee plunges from the sky and delivers a maximum-power Megaton Punch directly onto them, launching them through Pop Star as it is cracked in half during a quick cinematic before returning to the fight. (50%, spike)
Alternate Colors
1) Regular Outfit
2) Star Allies P2 Skin
3) Star Allies P3 Skin
4) Star Allies P4 Skin
5) Waddle Doo colors (deep red skin and a black face with a white outline and white eyes, black bandana)
6) Kirby colors (pink skin and pink face with red feet and blue eyes, red bandana)
7) Cleaning Dee (bandana pattern becomes Cleaning Kirby's hat, body color becomes tangerine, with green feet and cyan eyes)
8) Sailor Waddle Dee (simple hat change to reference another character)
That should be about everything. I really love the little guy, and while he's not my ABSOLUTE first pick to get in, he's one I debate about most often with others (both about getting in the game and what options he has for a moveset), so he's probably the character I've put the most thought into by far.