First off, I need to know if you would consider this overlay as "appropriate" before we move on:
[X]

Second, I feel like there's something I need to fix about the shading/lighting. She's suppose to be my vision of a river naiad (a woman made of water, or water formed into a woman figure). What do you think?

I think it looks very nice ^^ You can see really good that she's made out of water. Maby the only thing you could do is making lineart around the bubble-things, I think they'll fit in better with some lineart just like the Naiad ^^ good luck with it =3

Thank you for your feedback ^^ The bubbles were originally suppose to be part of a bg type thing, but after lining them they look much better. Results are on Azula's profile if you want to see, but I like it ^^

Yes, now they really fit better with the Naiad herself 8D Very nice overlay ^^

Perhaps you could make her lineart a bit blueish? It would make her look more transparent c: The shading also seems fine, though I'd make her "sparkle" (like water obviously) a little more c:

Good luck with it!