The fading differential doesn't matter as much if it is a quick quilt intended for use and abuse, and/or a quilt that is not meant to become an heirloom.
Do you have a sunny window? What you can do is place a square of each fabric in the window and leave them there for a week or two. There are fading requirements on cotton fabrics, but the requirements are shockingly low. It's been years since I researched this, but it seems to me that cotton fabrics typically will show fading within 70 hours of exposure to sunlight. If you can leave your fabric samples in the sunny window, you can periodically check their fading by placing them on your unexposed yardage periodically. That will give them an idea of the fading differential between your green and the other fabrics, and help you decide if it is worth using the green fabric or not.