You've got an excellent list! I would point out that customizing NPCs requires you to check "Allow Customization" in the Options menu.
Things that can currently be customized for NPCs are: skin color, hair color, eye color, hair style, hair length, fashion style, breast & penis size, butt size, height, plumpness, and muscle.
You cannot change a NPC's gender, that would kind of break things XD
We're looking into the ability to change an NPC's name and will add it in a later update.
Also due to the way NPC generation works, you are highly likely to see several of these NPCs just in the course of normal gameplay. For one of my characters the Quickieburger Organizer is also on the cheerleading team, and you can often find non-student Special Town NPCs at the River Rat.