powder blue?

Your yellow print would also look very nice.

What beautiful fabrics! Will be waiting to see pics of auditions of sashing and borders. Nice job.. Well done.

After reading all the comments you must be really confused!
The choice is your's but the best thing to do is to lay 4 blocks on several colors and stand back 8 feet and see which one you like best.. quilt shops usually let you do this. A mottled or solid would be best, don't add a print unless it's a tone on tone.

For some reason, navy blue popped into my mind's eye. I think it would make it pop.

Could you post a picture of your walls? I am having trouble imagining 'cobalt in a batik look" walls. It would make it easier to suggest colors.

I love your colors. I would like burgandy or a shade darker of the blue so everything can pop. Take a pic with the light borders and darker borders and see what everyone thinks?

As someone mentioned earlier, I think you are going to have to audition different colors both dark and light and see what compliments the beautiful colors you have in the blocks.

Post one with a white border and the other with a blue. You would not have to sew the borders for the pics. WOW, the are beautiful!

burgandy would be my choice