The closest I have come is WIlton cornflower blue for thew buttercream.
I never tried it in fondant. But if the buttercream and fondant had to match I would try that first in both.
I have found that white fondant is hard to recolor when trying to get a saturated color.
You can use the Satin ice color chart. I believe the closest would be 2 parts blue and 1 part pink. Then add white to lift the color to match your buttercream.