I have never had good luck introducing another cat into a house that already has a cat, but I did have a good experience with our old orange Tom (neutered) and a lost kitten that was here for a few days awhile ago... so I became hopeful that he might accept a kitten, maybe better than adopting an another adult cat.
Though there was a certain amount of friction....
At other times he seemed almost maternal.
They'd be indoor/outdoor on our little farm, but encouraged to spend time in the barn, where the mice are, once they grow up.
If we have a choice, would you suggest that two females might be better than trying to bring in another male? Or does it make a difference?