Can't answer all of your questions but I'll offer an opinion on a couple. Make sure your flannel is prewashed and dried in the warmest temperatures available to you. This will help tighten the weave. I used 1/4" seam when using flannel with no problems. Also used the default setting on machine which something like 2.0. If your flannel is a very loose weave, you may want to use a slightly larger seam allowance and/or shorter stitch length but good quality flannel defaults should be fine. I hand quilt so can't really offer much of an opinion on the walking foot questions but I've never used one. I have MQ's a couple of small quilts not using one and had no issues. I also do no use one for attaching binding and do not have issues. For that I do make my stitches a bit larger, though. I agree with your thinking that I don't think you would need to use one, however, for the project you are working on. Others with more experience may guide you better. Good luck.