If the cat has been neutered then the sex of the cat should not matter. Your exiting pets sound like very friendly companions and it seems like you will have little problem introducing your new pet.

However, seeing as your other pets are already mature it may help if the new pet is also beyond the kitten stage. While your pets probably behave like children, it may not help the introduction if the cat is too invasive, as may be the case if you select a very young cat. Also try to look for sociable cats and, if you can, see it in the company of other cats before taking it home.