I haven't decided whom to vote for yet, but here's ome feedback...
Atto - would have loved to see this in the finals, and like Val said it's got a very nice narrative element to it!
Kodabble, likewise would be nice to see it develop. A crit would be the strong lines from the hip down which sort of makes it look like she's got her bum beneath her tummy and legs rather than a tail... It's a bit confusing to the eye.
Valence, I really like this "nice and quiet" little mermaid even if she may be unoriginal. She makes up for that in the way she looks at the viewer and all that personality in her face, in my opinion. I do have a few crits... For managing one of those "T&A" poses, it seems you didn't actually work much on either boobs or bum... Her tail could use a better defined anatomy/structure and I think her boobs are a bit on the indistinct blurry side (come on, mermaids are the perfect excuse to paint boobs!) I also think her hair should be a bit more "bouyant" with at least strands striving towards the water surface (it could also be a bit softer and blurrier as hair often seems to look very soft in water).
However, I do love her face, her hands (yes!) and the highlights from the water crests above, on her skin. She's the kind of mermaid you'd LIKE to meet.
Which brings me to Banj's mermaid. This I would NOT like to meet... Not quite as elegant as some, this skinny, teethy thing is... scary. I think the nearest boob might be placed sligfhtly too close to the armpit, but.... maybe that's how these things look?
The black and white makes for a very stark image and I like the halftone pattern. And for some reason I especially like the choice to make a larger white bubble for a black signature, rather than just doing a white signature on black... o.O
I think I will have to decide which one to vote for, during the weekend...