I thought that's what they were! I have a Sapphire Olive egger...she is a FBCM crossed with a Cream Legbar...that is my best guess anyway, she was a surprise when I bought what I thought were 4 FBCM! I'm hoping to add a couple of the Legbars to my flock next year and breed them with my FBCM rooster/s.
Edit to add: If your girls lay a green egg instead of blue then they are probably a Marans/Cream Legbar cross!
This is my sweet Madeleine

You can't see her crest as well here, but she has one!
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A picture when she was younger...you can see her little crest!
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Maximus
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Marquis has more gold on his back feathers
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