After looking at the colors and prints it seems as tho almost every fabric has blue in the print. There is a deal of others colors all of which might go well with a soft greeny blue or
blue green that would provide just enough contrast to the green in the quilt.
I think perhaps a solid, don't forget, like I always do, to take the quilt with you and look at fabric in store and step outside in real light too. Not that it matters here it is usually gray for 9 months of the year but for those who live in the real world, I think it is a good practice, like when buying lipstick. I mean how much florescent lighting do you have in your house?
So check out match in natural light if you can.
Good work, and good luck, quilt is darling you two.