One thing that has not been mentioned is the fact that most flannel shrinks more than regular cotton fabric. This is why pre-washing flannel is suggested. If it is heavily quilted, it may not shrink as much, but that also means heavily quilting the entire quilt.
Satin is usually a dry clean fabric, rather than washable. And it frays,
Just my two cents: omit the flannel and the satin. Your colors are lovely and will work nicely together.