Ok. I have a female pied merle and i wanted to make pied black merle babies so would i breed her with a solid black male? Also how do i get them to breed. Once she hits her estrus put her in with him or let her stay with him until pregnant?
So first, Merle is a phenotype and the gene you are referring to is known as Roan- ro, which is recessive. The Roan gene doesn't behave like other coat types because it does not breed true; in that it often creates two phenotypes/coats, which are Merle and Roan. Merle mice are often Black Roan mice (but can also come in Red, Blue, etc), appearing as Roan with Black spots. Roan mice completely have the Roan pattern throughout their coat. Even if you breed two Roan mice together, you are still likely to acquire Merle mice and vice-versa. In summary, Roan and Merle mice are identified as different coat types; however they are the interconnected phenotypic products of the same gene.
Regarding your questions...
It is possible to have Piebald Roan and Piebald Merle. I am not sure what you mean by Piebald Merle and Piebald Black Merle, because they are the same thing (assuming no recessive dilutes).
I recommend keeping the buck and doe together until it becomes apparent that the doe is pregnant; when she has a large, golf-size ball abdomen.