The white one looks like faintly Siamese marked and the black one is a very faintly Vienna marked so, by adding white back into the overly black Vienna markings you might get some Vienna marked rabbits. Adding black back into the overly white Siamese marked you might get some Siamese rabbits. I think this would happen, but I could be completely wrong. You could also get completely different colors from what yours are, it all depends on what their ancestors are colored.
May I also ask, what would be the purpose for breeding them?