There appear to be degrees. It's debated to be a combination of genes making wavy coat by itself and astrex with rex. Then there are varying qualities of coat which would probably depend partially on the quality of the rex coat and then the amount of wave the coat got. They also change a lot while maturing with some becoming more ideal astrex and some fading away to look normal coated. I'm still waiting on my batch of 5 I kept to finish out their coats. I kept 3 that showed astrex and 2 that showed just wavy coat. Most of mine are chestnuts with 1 broken black, 1 black steel, and 1 broken red steel. Love that last one.
Black is a base color and very common when you cross things. Chestnut as well. If you let all rabbits breed uncontrolled eventually (it may take a few 100 years with all our colors) you should end up with chestnuts and maybe blacks. We just select for the more recessive colors to keep them going. If there is too little to select from such as select for coat first, then type, and eventually color you tend to end up going back to the base colors until you have a wider group to work with and can keep the rarer colors to work on their quality.
