I also have a way of last naming villagers. All my original villagers names automatically become the last name of their child.

Example: I have three girls: Waiata, Kia, and Lomai. I also have three boys: Nolo, Moto, and Tui. If Lomai and Tui have a baby, the last name will be Tui if it is a boy and Lomai if it is a girl.

After that I just keep repeating the last names. It's a good efficient way of keeping track of your villagers. It is also good if you like to see what original villager your tribe came from.