JoelHit, the article you link has precious little if anything to do with what Ethan is asking.
It sounds to me Ethan as though it's more to do with branding and practicaility -- albeit within the confines of the max character length that Twitter allows in a username. So the question reall is, do you want to be pushing the idea of an acronym in order to unite the character accounts -- or will there be enough recognition fed through from the web series itself?
I'd be inclined to suggest everyone sits down and has a good ol' brainstorm about this. For example, might there be a way for the series to feed its audience to one character's Twitter feed, and then via @ replies and mentions within that feed, spin off and "discover" new characters?
What I guess I'm saying is, you've got a great opportunity to explore methods of storytelling as well as marketing. That, to me, is more pertinent than the idea of tagging all characters with an acronym.
If pushed, I'd say that appending "fishbowl" to each character's handle would be a nice and sticky way to tag them, based solely on resonance (a fancy schmancy way of saying, "it sounds funny, so do it")
Bear in mind that the shorter the username the more you can say in a retweetable tweet. So keeping the number of char's in a username as low as possible is an approach that also contains some wisdom.
Sounds like a fun project anyhow! Best of luck with it!