Breed true, not really, if you mean for multiple generations.
In the first generation, you should get at least some that lay blue or green eggs, but you might get some that lay white or brown.
For each hen that has one blue egg gene and one not-blue egg gene, she will give the blue egg gene to...
Yes, if the chicks inherit the blue egg gene from their father.
You need one that has the blue egg gene, so it sounds like the fibro egger is your best bet.
When people say the pea comb gene is linked to the blue egg gene, that is not quite accurate. It's more that pea-or-not is linked to...
Do they both make the same shade of blue eggs?
It sounds like the two alleles may have no practical difference for most people, but I am finding it quite interesting that almost the same mutation happened twice.
I turned up an old post that might help:
Your Brown Leghorns are probably the wildtype, so e+/e+ and no pattern gene.
Have you played with the genetics calculator?
http://kippenjungle.nl/breeds/crossbreeds.html
I've found it helpful to just change the genes and watch the pictures &...