Well you know the answer you will get to the last question. So I will focus on the rest. If Leo is a strong personality then you probably need to get a less assertive cat. If Leo's personality is part of being a Maine Coon, then the new cat can not been a Coony. Female cats tend to be more assertive than males (though that is not the case in my house - actually come to think of it, it is the case in my house, it is just that Esther is a benign dictator). Getting something a little younger than leo, but not entirely a kitten is possibly your best solution. Something that has developed a personality so you can see what you are getting, to some extent.
