I have backed a couple of my quilts with fleece and no batting. Just a light weight quiltie but is probably too warm for Florida.
I don't always pre-wash my fabrics but I do use the dye catchers when I do. The one color fabric I always check though is RED! I wonder why when red was the first embroidery floss (redwork) to hold it's dye? (I read that somewhere) Seems like they could fix that with all our modern day advances! (I'm talking high quality fabric as well as the cheaper varieties)