Now this I can semi answer. while BBS is all one gene pool, if a FCBM has ONE blue feather its a DC, assuming the info I got this weekend is correct. So, while some of the chicks would be acceptable not all of them would be. So FCBM people are a little paranoid about blue genes sneaking into the black pool and showing up later. The blue people don't care as much as dark blue is good and adding black genes isn't a bad way to keep it dark. Some blue people care more however. Its the same thing if you are trying to breed silkies for paint, you need a partner that's black/black, not blue black, ( or that is the thinking now. paint thinking is still a work in progress)
I was doing some research as we were thinking about getting a blue hen to brighten up the yard a bit. If we do, I would not offer her eggs on here unless people wanted some color for fun. And of course, most people want FCBM's for egg color, and while there are exceptions, FCBM's tend to have much darker eggs then some of the other colors. This is not true for every bird, but is true for the breed in general.
