The ear lobe color does not help in this case.
Ear lobe color can sometimes help figure out what breed a chicken is. Knowing the breed will usually tell what color eggs she will lay.
But in this case she is a mix, and you already know what is in the mix. So looking at her earlobes will not tell you anything more than what you already knew: she has a chance of laying blue or green eggs.
For a chick that hatches from a blue egg, the chance of laying blue or green eggs can be as high as 100% or as low as 50% or somewhere in between, depending on the exact genes of the mother and the father. The other 0% to 50% of chicks will lay eggs that are brown or white, depending on what breeds are involved.