I don't have a clue as to the genetics on the single or double mane since I don't do lionheads, but as for the colors here's a quick breakdown of the basic ones. Since I don't know what you don't know, it will start out really basic:
There's five basic color genes in rabbits: ABCDE. They are in pairs so each rabbit has two of each: AABBCCDDEE. Each parent gives one letter to make the pair that each of their offspring will have. Traditionally, a dominant gene will be shown using a capitol letter such as "A" and a recessive will be designated by a lower case letter such as "a".
IF there is any dominant gene whatever color or pattern the gene is in charge of will be visible. If there's one recessive and one dominant gene, you will see the dominant color/pattern and the recessive gene will be hidden. The ONLY time you see the recessive color/pattern is if there are TWO recessive genes at that spot in their genetic color chart. When you don't know if there's a recessive gene hiding behind the dominant color, most folks will use an underline to show it's unknown if the gene is dominant or recessive.
A black agouti patterned rabbit is the most dominant color in rabbits. That's the 'wild' rabbit color and it's a color pattern. There will be white around the eyes, inside the ears and on the undercarriage. The genetics for an agouti rabbit is A_ B_ C_ D_ E_. All kinds of recessives can be hidden. A rabbit with AABBCCDDEE will look the same as a rabbit with AaBbCcDdEe. If you don't have any agouti genes in your herd, there won't be any fawns or reds since that's a requirement for those colors. So far, you've not mentioned any agouti color patterns. So, unless any of them have white around their eyes, in their ears and under their tail, all your rabbits will start their color charts with a double recessive 'aa' for 'solid' color patterns.
The next color gene, B, is pretty easy. If there's a dominant B, the bunny will be black. (or some black based color, dilutes and extensions can change the basic black). If there's two recessives in this spot on the color chart, the bunny will be chocolate. It sounds as if a lot of your bunnies have the double recessive for chocolate, although the black double mane will have the black gene. If the black bunny has chocolate offspring, then you will know it has the chocolate recessive to go along with the dominant black gene that you see.
The C gene has a lot of variations on it for light and dark chinchilla, but we will ignore those for now. The basic expression of the C gene is for Color or if it's a double recessive, then a ruby eyed white (REW) which is also called Albino. If your rabbit is anything other than an albino, it has at least one dominant C gene. If it has two recessive genes, then you have an albino and you won't have any idea what other color genes the rabbit may have since the albino is a whitewash that covers up all other colors.
The D gene is for Dense color when there is at least one dominant D gene and for dilute colors when there is a pair of recessive 'dd' there. A diluted black - aa B_ C_ dd E_, will become blue. A diluted chocolate - aa bb C_ dd E_ will become lilac.
The E gene is for extension of color down each hair shaft. Kinda an odd thing, but bunny color genetics can be a bit odd sometimes. When there's a dominant E in their color gene chart, then the full color will extend down each hair shaft. If there's a pair of recessives, 'ee', then the darker color pigments are omitted and all you'll see will be the tawny yellow pigment. This is where you get tortoiseshell colors in the 'solid' color of bunnies (double recessive 'aa' at the beginning of their color chart) and the fawns and reds with the agouti colors of bunnies (the ones with a dominant A at the beginning of their color chart).
The bunnies here have their color genetics written on their pedigree which is helpful for keeping track of the recessives when we find any.
