Besides the outside cats I am trying to keep fed, I have 10 of my own.
I started with one (doesn't everyone?), and got a second to keep her
company. They didn't take to each other. They got to the point after a
few months where they tolerated each other but never became buddies. I
think though, that they each appreciated the other cat being around.
Just comfortable to see one of their own kind. All of their
personalities are so different. I have 2 who are brothers and have
grown up together for 5 years who fight like cats and dogs, as they
say. I have had to pull them apart a few times. Others who didn't like
each other at first now cuddle with each other all the time. A kitten
would absolutely be best. Another adult cat may be more threatening to
the first. A baby is not seen as a threat. It's a hard call to make
but (if I didn't have 10 now) I would always try to bring another in.
I am at my limit in terms of the expense I can handle. I can't bring
any of the outside cats in. I just try to keep them fed, but my own
have to come first. But if I had just one all over again, I would look
for company for him/her. Even if all they do is lay across the room
from and look at each other.