deleting the Maxis pre-fab characters isn't possible at this time without hacking the base game files - which leads to various other issues. I don't recommend it. I suppose a particularly smart person might find all the assorted file parts and make a default replacement package, but I have never been able to locate all the files in two years of digging.
Sorry for the delay in replying to the questions of the others, but I have been away from the forum a lot dealing with a health matter. But the files with those name patterns are the user made Sims, I suppose someone might take a whime to type junk code as a project name, but I have never seen that.
The naming convention works like this:
The Creator ID is usually unique for each installation of the game - if you add an EP or re-install the game this will change.
The Sim Model ID is randomly created at the time you start your new sim in Body Shop.
The File Extension is the package format.
You have no control over the values that BodyShop uses in these sections; after the file is created you can change them, but that really isn't advisable.
Other projects , let's say a makeup file for instance has a random alphanumeric ID generated by BodyShop followed by whatever name you chose to give your project. So the two are fairly easy to differentiate.
