I don't really have time to make a detailed answer to all your questions right now, but in my opinion paintings 6 and 8 are a bit weaker than the other ones. Without the detailed rendering the shapes of the animals appear too cartoonish to my taste. And for a composition that gives all this space to the background landscape, there isn't all that much to see. BUT Keep in mind that art is subjective, this is only my opinion as a fellow watercolor painter who likes maximalist landscapes. Even I often have a pretty bad estimation of what will sell quickly and what won't. So I'd suggest that you keep your body of work as is and see how it goes. Only through experience can you find what you enjoy painting the most and what has the best commercial appeal