We have a female yorkie (Cairo) and a male minpin (Tucker). The combination is just great. The owner of Cairo's dad has 2 females and 1 male and in their house the older female is quite dominant and does not always get along with the younger female, but the male gets along with both of the girls hust fine. So from personal experience, I would say to get a male.
As for names, I've always really liked the name Spike. It just sounds so tough.