Thanks Tinkster! I'll give it a whirl!
[EDIT] Unfortunately, whenever I edit those files and reboot, the files and usernames are back to being what they were. Yes, Micro Core is installed to the HDD (not CD), and there is no CD in the drive. I'm not that nooby.
[EDIT 2] Wait, I figured out that this is because Micro Core copies to and runs from the RAM by default. --facepalm-- You have to modify the microcore gzip files in /boot on the hard disk for the changes to take effect. Bleh.