Gorgeous quilt! I agree that 80/20 batting and quilting individual blocks would finish it off nicely! I also would choose variegated threads to blend with the background of the blocks. Some of the Sulky Blendables coordinate with the McKenna Ryan fabrics. You can look at the chart and pick individual spools or they also sell a bundle (which costs a bundle). Here's a couple of links for reference:
http://www.redrockthreads.com/thread...read/33304.asp
http://www.ericas.com/threads/mckennaryan.htm