What is confirmed about pets
You can roll for rare pets, pets make money even while you are away, and other players can destroy bases and steal pets. That is enough to plan spending and protection, but not enough to publish a named tier list or exact value calculator.
A pet in this game is both an income source and something exposed to multiplayer risk. When you compare pets in the live interface, consider what the game shows about income, how much cash or time it took to obtain the pet, and how difficult it would be to replace after a steal. Do not treat rarity alone as proof of economic value.