You can make any quilt beautiful. Often, they don't look too appealing until they are done. Here's what I would do...take your main fabrics and audition them with every color of the rainbow and see which one makes them pop. Then add a bit of that color in with your 9-patches...maybe the centers, or in setting squares. That color can also be used in the binding and/or backing. Also, you can add white in there to dilute the ugly colors. I'm sure it will be beautiful when its finished, and they will appreciate you using "their" colors. Good luck.