I'd hate to be stuck in a cage my whole life! If Simba doesn't like cats and you don't think that it will work out for you to bring him in then just get a cat and let it be outdoor only. That's the good life right there. Cats are meant to be outside and they can take great care of themselves(if they still have their claws). If you choose to adopt an adult cat(which may be best)then I suggest getting a cat that has been outside most of it's life so it doesn't go into shock. Perhaps and neutered tom that would have no interest being inside at all?
Please don't go along w/this idea of keeping a kitty in a cage. I hate it that they do it at the shelter even though it's only momentairily. I respect the shelters that take the time and money to have a catroom built so the kitties can wander freely.
My cats all stay outside(except for one but only because she has babies)and they show now interest in being in. I suggest getting atleast two because they tend to stick around better.
Good luck