Over the last 35 years we've always regarded 3 cats as optimum!
Originally, we were guilted into 3 over a period of 2 years:
1st was a female rescued by my flat mate - she didn't get on with her existing male cat, so moved into my bedroom.
2nd was a male kitten rescued by another flatmate at 3days old, we all blamed aforementioned male (he was promptly neutered), mother cat had deserted 3 kittens - between us we hand reared them, somehow one became mine!
We moved....
3rd cat was another male, after a year, neighbors moved away, leaving a male cat because "the new house wasn't suitable ", actually, he didn't match the new decor. (He was a v expensive pedigree from Harrods)
In all, we've had 15 cats over 35 years, always 2 boys and 1girl, never really had a problem. Some become really pally, some ignore each other.
Personally, I'd go for a male kitten, if possible (neuter asap) and let your female teach him who's boss. There's plenty of advice on here about introducing cats.
They'll soon settle, you never know they could become best friends.