I love the colors that you have picked. I do think #5 and 6 don't really go with the others and should be in another quilt. The first 4 are bright and 5 & 6 are kind of muted and would do better as a background with other colors. IMHO Your quilt will be very pretty with a white background fabric. Let us see your quilt when it is done. Purples are hard to match sometimes.
Sue