I have personally have a lot of luck with only having 1 female and as many males as I want. This is just my preference.
I find that having male dogs are great because I am always alpha female around them. I feel it makes it easier to be pack leader.
I currently have 3 males and 1 female (1 male is not a Yorkie) and the dynamics are pretty good.
I think 2 males is great, but a male and female usually get along well. When you add another female is when I usually start having conflicts because females like to be the boss. If you get a female I would expect her to probably be the boss, not always, but most of the time it works that way.
Good luck and I am sure that whatever you choose it will be great. If you have a very outgoing dog, I would get one of the less outgoing, not the shy or timid, but not the pack leader. If you have a less outgoing dog then go for the leader of the pack type dog for this new puppy.