Happy Halloween

It seems that you put the effort on this picture, the colors, drawing 6 characters in whole pic can be difficult, i admire the work, but if you don't put the description, i would have said that they are clones for a pretty simple thing, they all have the same face/expression, i can't understand if you couldn't imitate the styles respective to each character, it can be hard to do, but they all seem to have the same eyes and head shape, not to mention copy pasta for expression, hair style isn't enough to difference a character, they need some kind of different gesture, different eye shape or nose shape (how they can breathe with those btw), or something that shows that they are different from each one even if this is a happy moment, maybe one is shy, the other is a bit more prideful, something like that.
Bright colors or interesting design won't help that much if at the end they are all clones, this is not to make you sad or anything, im just trying to help you a little bit you have the talent, with those small changes your artwork would be much better, over here you can find good tutorial about face gestures or even common photos can help with expression (because i know that even you can't have the same smiley face every time)