Great! You got a hang of it to use the right sources.
I get your idea of making it look playful. It looks pretty good. I like the bright and playful colors along with the drawings itself. You did a good job executing what you had in mind. BUT! I have two small complaints. Due to using a lot of effects on the render, it has gotten jagged (blur the jaggies or soften/remove some filters with masking). Aside from that...it would look better if you remove the brushes/effects on the vector and just make sure she blends in with the bg color-wise (which you already did). In other words, leaving the vector "neat" or "clean" looking will do your wallpaper more justice.
Keep'em coming ~
