Color means absolutely nothing in Mini Lops, very few points for color, so often they are all bred together with little regard as to color. This creates rabbits that carry a lot of different genes, I had a tri-color ML doe that would produce tri's, torts, chinchillas, sable points, and of course harlequins and brokens, never tested her for REW. Thats just too many colors for one rabbit to carry, not to mention chinchilla is a big no no with a chestnut based color. You already know to avoid chocolate because it will make the blue eyes look violet, you also want to avoid REW or REW carriers. Get a REW buck and do test breedings to avoid adding it into your lines. I'd avoid Chinchilla personally, unless its the best Mini Lop you've ever seen. Other than that ignore color, look only at type, keep the best vienna carriers and breed them back to their sire or to each other. I built my BEW line with one buck, added in a doe later, its easy, all you do is add the gene, breed back and you've got BEW's. I personally have stuck with black otters in my BEW program for the most part, personal choice, and in Mini Rex otters are of very good quality, right up there with castors these days.