A lot has changed since I made that last post and was unemployed and living in an RV. Now I have moved into a nice house with my brother's family and am becoming an in-demand freelance graphic designer so I no longer have the free time I once did. Otherwise I'd be jumping on that opportunity because I think it would be a blast to do that and experiment with materials as well. I love all kinds of art, though, like I said, I'm not familiar with sewing and making cloth items.
I recommend finding a place that sells high quality templates in the style that you are interested in, order a couple, and study them. Once you are familiar with how they are used and constructed you can probably make your own design fairly easily. You can probably get by with using a template for a mouse, rabbit, or guinea pig, broaden the face (if it's a super realistic head), change the shape of the legs and ears, and fabricate a suitable tail.
Maybe you can get some bristles off a cheap whisk broom and hot glue them from the inside for whiskers. If you put them near a heat source like a hot glue gun or heat gun you might get some nice curvature to them if you're careful. I imagine there are ways to brush dye over the fur to darken the tips along the back and tail and make a nice color pattern but you'll need to practice with that before you use it on any pieces you care about to make sure it's possible.
I imagine there are tons of books and articles available on how to make plush animals that can help you immensely and go far beyond your chinchilla project. Once you have that knowledge you could likely create far better templates than I could and learn more about sewing techniques that will help you in your art. And studying graphic art and drawing or painting animals will help you as well. Be careful to not try to move to fast and get frustrated if you should be doing simple things before proceeding to more complex and realistic designs but you might just find that you have a knack for it.