For me, the characters are the characters. You make characters that are beautiful to your eyes, and that's what matters. Whether they have the features I like is irrelevant. Your eye should be the first eye.
Lighting. You're using the default skydome/HDRI. I think that's fine, but you're leaving it in the scene. For more final images, I wouldn't render that HDRI, myself. It looks like you're using a default that way. It's somewhat distracting, from the Daz user perspective. (Uncheck "Draw Dome" in the Environment - Render Settings. Add some other background in.)
I'm always a huge advocate of post-render processing. Some say it adds time to the process, but to me, images look incomplete without some post-work. The light levels, the skin tones. The skin can be made to look richer, I think. It looks very "3D render", which to me is somewhat less than a full artistic vision.
Otherwise, Daz is Daz. We all use it here, in this thread. It's a starting point. Don't worry about the engine as much? Like, fog. I could do that in seconds post-render, where it would take much longer and add overhead to the use of the engine.
Daz Iray is a fun thing to tweak, but it should only be taking you part of the way to the end state. These days, I mostly tweak it for speed, and do the effects afterwards. Iray optimization can be a huge time sink, so don't feel constrained by what you can do in-engine. I think that can be a trap, and you can waste a lot of time in the engine for little effect.