Concept art has many facets. One of the most important ones is storytelling. Your concept could just be of a generic creature someone could get across, but won’t think more of. Or a leading one, like Flax, a prominent mount in the storyline. Both types have a clear overlap in how you should approach them. Habitat should be taken into account as well as functional anatomy based on their habitat and behavior. But there is way more to a character or creature that has a prominent place in a story. And Flax, a Lutherial Vixen is a good example of that.