First off, wicked idea!
Secondly, the shade of her skin looks remarkably similar to a character I have cosplayed before. I may be able to help!
Midna has a light blue complexion, and I used a Kryolan water based body paint. It worked amazing.
They have a wide variety of colours and shades, and it is really easy to apply. I found I got a smoother, more realistic complexion when I applied the paint without water, and taking my time. (it does take longer this way, but totally worth it!)
I had the paint on the majority of my body, as you may also have to do, and it stayed on remarkably well, excluding my hands, but they are a tricky place to keep even.
I sealed the paint onto my skin using hair spray. There are designated body paint sealing sprays, which granted, are probably better for you. But I found the hair spray worked a treat.
Hope this helps!