Although I can't say for sure that KI hasn't changed any of the pets, it is most likely the result of hatching/breeding the pets to increase their stats.
more then likely this is a direct result of specific mixing of pets. my theroy on it is that someone likes the look of pet A but likes the skills of pet B so they mix them together untill they have a pet that looks like pet A with the skills of pet B. its actually a really long process but well worth it in the end.
