HI Diamonds! What beautiful fabrics. Would you maybe consider throwing a soft cream fabric? Either way, with just two (or three) colors, your design load will have to be carried by the intricacy of the block rather than a mass of color.
A larger sized block which allows for a variety of components (large and small) would be the direction I'd go..with maybe a sashing thrown in and a wide border of one color (which would give you a chance to show off some fancy quilting patterns!!) good luck, and be sure to keep us posted.