That is beautiful! Really nice fabrics, and I love the crumb blocks with sashing.
I personally hate using "stretchy" fabric for backing when doing machine quilting - flannel is bad enough, but oh the PAIN of fleece backing! I did do a couple this past year for a 4H charity project, but I hated every bit of it, and only did the minimal amount of free-motion quilting needed to keep it all together (and no batting). I ditto the person who suggested tying it instead.