I actually think both of these look perfect the way they are! I don't really think any changes are necessary, and to be honest, some of the comments here feel unnecessarily nit-picky about small details. The silhouettes are strong, the colors are fun and bright, the hair is cute, and they match their street clothed versions super well!
About having trouble coloring glowing parts: if you're coloring these images digitally, there is a pretty quick and easy way to make stuff look like it's glowing!
Use a soft, airbrush or "spraycan" looking tool in programs like SAI or Photoshop, and on another layer on top of the colors and lines, go around the edge of the colors that are supposed to glow and use that tool there. You don't need much to achieve this effect, all you're looking to do is make it seem like the light is coming through and around the edges of the material that isn't glowing.
You can fiddle with the opacity of the layer as well as layer effects like overlay or screen to see how you like the effects of those, and further down the line you can think about backlighting and such.
Here's an example of what I mean:

You can also try changing the line color from black to green/blue/etc to help with the glow-y feeling.
Maybe this is a technique you already know about-- but I find it works wonders to quickly get the job done and give out the glow effect without having to spend hours getting it where you want it.
Good luck!