I'm pretty sure Joann's carries both the Hobbs 80/20 and the Mountain Mist Blue Ribbon 100% cotton. As a beginner, you might be happier with the 80/20 because it has the fluffy element to it. The Blue Ribbon is considerably flatter looking and can disappoint unless (like me) you like that thin soft look after washing. I haven't seen the good battings at our Walmart, but it's a small one.
A lot of people mix hand quilting with machine quilting. I would recommend doing the machine quilting first, as that will stabilize the sandwich for your hand work.
For the spray basting, check other threads so you purchase a good brand. 505 and Sulky are the two preferred brands because they don't stink you out of house and home (but still spray in a well-ventilated area). Sulky is environmentally friendly now too.
I would post another question to ask how fleece holds up over the years. I have never used fleece as a quilt backing, and I am unsure if the spray basting would stick to it. Also, fleece is stretchy so it's easier to get distortion in the backing even if you starch it heavily. You might want to ask about a flannel backing and how they hold up over the years. Again, I don't have a quilt with a flannel backing so am not sure if they eventually pill. Personally, I would use a cotton fabric for the backing just to make sure it will last without pilling, especially if this is a quilt that will be machine washed and dried many times (as most loved little blankies are!). However, I would recommend a print design backing fabric instead of plain white. Any solid color backing will highlight mistakes you make on the quilting; patterned backing fabrics hide mistakes so you still get the nice textures but no gross imperfection are staring you in the face every time you look at it. (And usually it is only the quilter who notices these gross mistakes anyway.)
Also, do some research on threads to use for your quilting before you start. This can make a big difference in the result. I kind of like the combination of a variegated thread on top (adds interest) and a fine thread on the bottom (hiding mistakes). A lot of people like King Tut variegated for the top and So Fine or Bottom Line for the bobbin. Make sure your needle is the right size for your threads too. You probably want to avoid metallic threads as they can be considerably trickier to use.
I'm sure your quilt will be much loved over the years. The biggest problem is usually not how pretty a quilt is (even "ugly" quilts become loved through usage), but finishing the quilt!