I like the top two with the back lighting. Dramatic. Which color would depend on what you want out of the painting. The red one is the more natural color palette and I lean towards that one as my favorite. The green one is cool too, but the dress gets a little lost in the dark. Yeah, I vote the red one. I like it's values, lighting, and natural color palette the best. The blue one has a nice moonlit feel if you want to go that way. And the only reason I slightly lean away from the purple and green is because the colors are interesting, but they don't explain themselves. If you GAVE them a reason other than a cool, interesting color scheme I'd say any of them could be valid. An acid green rain going on for the first one? Some sort of fabric that cast purple light on the last one? Great composition, character, and color comps!
I like the top two, too! It felt like she was sneaking back into her tower at sunrise after the Prince failed to meet her at the assigned time :( sad. Did you paint it yet?