i just go for appearance and everything else is an added bonus. sometimes it makes it more entertaining, such as my reigen arataka cat being a pleasant personality with higher base luck (aka magic aka psychic powers) than mob, or my yuji itadori cat having base 6 agility. the only thing i try to avoid is a cat that has children, something about it makes me feel bad
of course even then i tend to be pretty loose in accepted appearances
reigen should be orange but is instead apricot, shou and shoko are trade winds instead of having a standard coat, but to me it just makes it more personal. these aren't just little guys i turned into cats. they are little guys turned into MY cats.