Okay, you know it is going to be a wall hanging, that helps because you know that there won't be a lot of hugging, pulling, washing, etc. I would put a stabilizer on the stretchy stuff and go for it. You might also check your stash and add just a bit of fabric that would help in organizing the the picture a tad better. And you can tell them that you added some fabric to highlight the family's contribution fabrics plus letting them know that you added just a few fabrics to put your signature quilting fabrics. Just a thought. Lay it out and move it about and go for it. It is actually the fabric of the loved one that they want to pass through the family and that is the important thing. Go for it, Twinkie!!! And please share it with us when you are finished.