I think your quilt really needs these range of yellows: without the brighter, it would be dull, without the paler, it would be too harsh...
As for the border... I would consider a rather small strip of one of the darker blues (not the darkest, may be the third one) inside, an even smaller strip of one of the paler yellows (again, not the palest, maybe the second), and a wide strip of the same blue on the outside... Or eventually middle blue, than a pale yellow, and then a darker blue.