On my two sided quilts, I chose to quilt for the side I considered to be the front. The echo quilted flowers from the front on one simply added a design element to the back. The second one had pictures on the back so I did try to not sew through any eyes. No reason, except it didn't feel right to sew on my granddaughter's faces.
I second the choose a side - maybe use a blending color like pale gray on the back.