This is rather good. I did not find any inaccuracies in this and your description of the Shadowland in the series is really good. Perhaps those rabbit shapes are actually real rabbits that had previously been taken by

?
I found it rather strange that you actually analyzed

being the first rabbit in a scientific manner, but your conclusion makes sense. In the book, it was said that he had "many wives", but since he is the first rabbit, where they came from is a mystery which unfortunately remains unexplained.
Finally, I think it would be a good idea to add a paragraph about

, if possible. It is said that he "had the power of the sky and the power tof the hills and Frith had told him to order the world as he thought best", but apart from that, exactly what he is isn't very clear. I remember reading somewhere that he might be a representation of humanity, but I can't find the link anymore...