You're getting ahead of yourself re: studying lighting. Work with basic forms so that you can develop an intuition for how light behaves. Study spheres, cylinders, cubes, pyramids, etc. Find objects in real life that have simple forms (coffee mugs are often cylindrical, a thick paperback is a rectangular prism, balls are spheres, etc), and draw them in various lighting situations (different times of day, or if you have a lamp or flash light, position that in various ways).
Study more complex forms such as animals later, but when you start that, try to break them down into the basic forms. Once you've gotten comfortable with simple forms, you'll find that complex forms are also much easier.
You seem so focused on details that you seem to have missed the most important change in loni_art's edit: the focus on the forms (and consistent lighting), whereas your original had lighting that made no sense, and details that drowned out the forms. Their edit is not without problems, but its clear forms and clean shapes are something you could learn from. The anatomy in their edit may be incorrect, but every body part is clear and readable.
Edit: Your recent edit is better! The body reads much more clearly. Watch out for how the legs are attached, though. Look at ref of real minks, you'll find that the upper parts of their front legs attach differently from how you think.