I went to the Linda Franz site and clicked on the book with the pattern here
http://lindafranz.com/shop/lucy-bost...the-crosses/31
There were 3 colorways the one on the far right was with medium and light fabrics and like ube quilting stated the colors you selected will make a soft and relaxing comfortable quilt. And if that is what you want these will be wonderful and sufficient.
If you want something more dramatic and with pop as suggested the first two colorways show some options with a dark also. If you do want the effect of a dark I think a dark purple or green would work better than black or brown.