You could use monopoly to quilt through the designs. It would look like the design is on top because the thread lets the embroidery show through. I've seen it done this way and it looked terrific.
Or you could crosshatch til you reach the designs and then echo around the outer edge of the design. This way you would also want to anchor somewhere within the design to not leave gaps. It would also be more labor intensive.
Hope this helps,
ali