A lot depends on the batting you choose. Some battings will allow backing color to shade through; other battings are totally opaque.
Warm and Natural will probably not allow an orange backing to influence the top at all; however, compared to other battings it is somewhat heavy and stiff in drape (the stiffness does soften with each washing since this batting is primarily cotton).
Hobbs PolyDown would be a good batting for this quilt because it is light in weight and offers a lot of softness and loft. However, it would probably allow a bright orange backing to shadow through to the top.