I know she has done a lot of research on the history of names she uses. Like Minerva is the goddess of wisdom and Filch means to creep around or lurk around. She did so much study as to make the names fit for each character and what not. I know she chose Harry though just because it's her favorite boy name. A lot of the ones she just made up herself though, like Quidditch and muggle. She's so brilliant I can't stand it lol. I think my favorite name has to be Dumbledore's full name though. Albus Percival Wulfric Brian Dumbledore. It cracks me up!