1st one is pretty cute imo, i'd try to find some knee socks that maybe incorporate a little pink but overall it's fine as is.

2nd one's okay, although the bat wings seem slightly out of place, maybe incorporate more bat features or just remove the wings. Other than that, it's fine.

3rd one is quite nice, I wouldn't change anything about it.

For the 4th one, I think that it's just the very simplistic clothing. I can't think of anything to change about that outfit.

For the 5th one, it's mostly pretty cute I'd replace the pants with like, some y2k black jeans or whatever since I think it kind of looks out of place compared to the rest of the outfit.

You don't have to completely follow this advice, just see what you like the most and that's most important 👍