The mistake people make with Waluigi and Toad is that they count props as a gameplan or playstyle, so that Waluigi using a tennis racket becomes a unique gimmick. Thing is, “sports” can, projectile manipulation notwithstanding, not substitute a gameplan and is rather a visual coating over a more robust playstyle. Look at Villager. His playstyle is not “hurrhurrhurr, I use da animal crossing items”, but it’s a special kind of hell walling that combines quick projectiles with long-range missiles and a tree obstruct. Isabelle does the same, with a more active trap and a get-off-me grab. The Animal Crossing items aee arranged in such a way to facilitate that deeper playstyle, and while their items do represent the classic Animal Crossing hoarder, it’s not their prime gimmick (that would be Pocket) or their playstyle (which is bullet hell)
I think that representation (referencing the game's items and such) and playstyle have to be developed simultaneously, side by side.
Villager uses the Animal Crossing items indeed, his/her playstyle is decided according to what the character does in the original games. That bullet-hell-like playstyle is possible because in Animal Crossing there isn't much that can translate well into an "attack", so they went with the items which feel more like weapons the most... the truth is, in fact only a small amount of Villager's attacks are indeed projectiles, most of their attacks are stuff like the umbrella, pulling out grass from the ground, digging with a shovel, using a wooden stick, and so; the few projectiles are the most defining attacks because they are the more useful when Villager is placing their traps on the stage, to control the space. The playstyle is a derivation of several different technical aspects of the character, for sure they didn't think "let's go bullet hell for the sake of it". In the original game, the character has limited mobility, he/she builds and arranges stuff, and can place traps (but that's already an item so we can't use it): let's make the character static, give them something to do in place, and equip them with some long range stuff in order to defend the area when they're standing in place. Offcourse, the in place stuff has to be traps, not the actual trap item but stuff that can act as traps for the opponents regardless.
Playstyle is also a relative thing, relative to what the other characters already in the game do. If there's a character who already has a similar playstyle, maybe it's better to change it to something different in order to keep them more unique. This is why Kazuya was chosen over Heihachi right? He does have the devil gene, he can transform and shoot stuff... if he didn't he would have been just another Ryu-Ken-Terry.
My point is, I disagree about playstyle coming first and representation last, I think they have to be done simultaneously, else you are doing something wrong* (*Ganondorf).
EDIT: On top of that, there's also the personality of the character to take account of... I don't mean the actual personality, but the "feel", which consists of animations, visual and sound design (art style), expressions etc. This has nothing to do with playstyle but it still plays a major role into a character's uniqueness.
