At the very least I would test the fabric you plan to use for bleeding. Looking forward to when you quilt, you may want the option of marking and if you use a water soluble marker you will need to wet it to get the marks out. it is pretty distressing when you are all the way done and you spray your quilt with water to remove the markings and having your fabric bleed.
Also if your wall hanging will use fusible web for raw edge fusible applique, many factory applied sizings will impair the fusible from fusing properly. This is especially true of Mistyfuse brand fusible. The fusible will not fuse properly. The only way to remove the factory sizing is to prewash.