I think the reason why no one was colouring it in was because it was all on one layer. It makes it very difficult to colour and looks a bit strange if you use the fill tool. People like it when there is a lock alpha colour layer and a separate layer for the lines. Another thing is the shading so that it looks less flat.
I hope that is helpful and that I haven't hurt your feelings. They were very cute lines and better than what I could do!
Enjoy!
