...as for chimeras
Oh chimeric embryos, that is exciting, well most i know are ones creted in the laboratory. In a certain stage of developement they will fuse two parts of two eggs togethere and axolotl will form. Use to study things like fusing a genetically fatal disorder guy with a heathy one, study of pigmentation, cell ressearch, grafting, etc. I will just say this, the way axolol immune system handles transplants is amazing, if your ever up for a fun read! I do not know of any chimeric axolotls outside of the laboratory.
you know that picture of those axolotls with a black head and a white body? Laboratory Chimera from my understanding.