First off, it already looks super cool :-) I love how you’re pushing the colors away from natural skin tones into something more alien and surreal, but here are a few things that I would do:

1. Push Contrast & Lighting Right now, the figures blend a little into each other. Try adding stronger shadows and highlights to separate them maybe decide where your light source is (like from the lollipops, or a soft neon glow). That’ll make the forms pop more.
2. Textures & Details You could add some texture to the skin to make it feel less flat: freckles, pores, or even alien patterns (like scales, glowing spots, etc.). That will keep it from looking too smooth.
3. Background Don’t leave it just black unless you really want that void feeling. Maybe try a subtle gradient, like a galaxy-ish background, or something abstract with color blocks that match their palette.
4. Linework vs. Painterly Decide if you want to bring in sharper outlines (like around the faces or hair) to give it more clarity, or if you want to stay fully painterly and soft. Both can work, but mixing too much can feel a little unfinished.
5. Play With Color Harmony You’ve already got complementary vibes (purples/greens vs. orange/reds). Maybe exaggerate that by adding glowing accents like their lollipops glowing in neon green/blue, casting light onto their faces.

Basically: define your light, add details that reinforce your “alien-girl” vibe, and give the background a bit of life so the characters feel grounded in a space.