The blue can be to some extent an imperfect recessive or partially expressed recessive -- still showing blue but having some of the qualities of the seal/chocolate color. The dilute factor is even more difficult to deal with.
Of course it's a crap shoot -- that's what makes it so much fun! My younger dog's breeder had to laugh at the mathematical inclinations of Ruby's mom -- she was a Yellow bred to a yellow-factored Black, which should mean 50 percent yellow and 50 percent yellow-factored Black. She had TWO black males, TWO black females, TWO yellow males, and TWO yellow females. She really likes symmetry in her litters . . .
I think you are right; but what’s great about it is they said it couldn’t be done. Until my breeder came along; it couldn’t; but she knows genetics really well. It took them 30 years. Even the breed founder has never done it. LOL
I never knew that about the blues and lilacs having had one of each. My lilac had the bluest eyes you have seen. They were just like the blues of the ocean. You learn something everyday.
I love it about the labs. My handler/trainer breeds blood hounds originating with a line going back to his grandfather. The grandfather’s dog had a star I believe on his hip and ever since then if you breed with that line; you are going to get a pup with a star on it’s hip.