You saw a cool image and you were inspired. That's great. Let's look at what your reference is doing which you haven't yet spotted:
Every character has a pose to them and they convey a simple emotion (besides the girl on the right, about whom I have no idea what that pose is supposed to signify). Yours suffer from lack of anatomic and emotive skill and therefore do not. I suggest instead of looking at how to make their hairstyles distinctive (which you have achieved) you look more into the principles of body language, anatomy and to start drawing from life. There isn't much to tell on the pixel art level rigtht now, as what you've shown is preliminary. If you still want pixel art critique, carry on with drawing these and post again and people will help you fix colors, aa, banding, dithering, the pixel art issues. But I do suggest you examine your inspiration and disseminate the active difference between it and what you do: it's not 'we're using different characters', it is 'the person that drew this has a more solid understanding of fundamentals about how to convey shapes, bodies, moods and effects than I do'. The road from inspiration to aspiration isn't such a simple step as the one you're attempting here, you need to internalize what you filter from outside sources and not define your own artwork so closely after what it is, but its general aspiration.
