The only alternative name I can think of for the pair is "express" and "general" - but even then it's probably not fitting for one reason or another. This very much reminds me of trying to come up with names for objects used in programming languages. No matter what you come up with it won't really fit and due to the evolving nature of things will end up being wrong or misleading in the near future
For this reason I think if I ever had pets, I'd just call them "Cat 1", "Cat 2" and "Cat 3" etc (assuming the pets in question were actually cats)