2D cosmetic customization alternatives

Hey, me and my friends are making a 2D platformer game, and we wonder what’s the best way to bring in cosmetic customization. In 3D it’s pretty simple and self explanatory, but in 2D it’s a bit of a struggle. Keep in mind that this game has weapons, quite an amount, and it’s pixely. My friend already made idle and run animations as concept, but the question is, is the only way to customize characters (or guns etc) is by creating a separate idle/run etc animations for each and every character/gun skin combination? That sounds stupid and a very wrong way to do it, but that’s the only way we can imagine we could do it right now.