If one of the labs and/or golden retrievers had a parent who was a black dog... That might explain it! Sometimes (even with dogs) the "family gene" skips a generation!
:) Hope this answered your question!
Labrador puppy's are usually more white.
Um, no. One parent has to be a yellow Lab to do that. Actually, you are wrong. A chocolate and a black lab can have yellow puppies. I have had my chocolate female bred with a black male and they had all 3 colors. In fact, she even had a white male which white labs are rare.
You never know - could be golden/yellow, chocolate, or even black. These are two different dog breeds.
The puppies will vary in appearance, but likely have a mix of traits from both breeds such as a golden retriever's longer coat and a lab's shorter coat. They may have a color range from yellow to golden, with potential for chocolate or black accents depending on the genetic influence from the grandparents.
A mutt
up to 10 puppies
Yes, normally.
Yes
the same symptoms in a golden lab.
Black
It would depend on the type of lab, but yes, they can.
none