I honestly don't think there is anything diabolical involved. Variety is not sitting around just waiting for every piece of information for DS alone- it has hundreds of other projects that it is reporting on. It gets what information it is given to publish, and if it's incomplete to us, it's because as MB said, it is because that is all the info they have at present. It doesn't mean it won't publish more later. I don't think the writers at Variety are sweating it as much as we are!
There could be any number of reasons why Bella's character wasn't named, from either that they felt the main point was to name the actress and the type of role she would play, not thinking this character's name was necessarily important (YES, I know it's important to us diehards, but to most of the film world it is just a detail), or that she will possibly be a character that is neither Vicki nor Maggy and the name thus not important right now. For The Rum Diary, I remember it was awhile before all the characters werie named, and it ended up having to do with one main character being omitted and others being combined- it took awhile before the eventual names were listed. Another possibility was that somehow the name could be a spoiler of some sort. For Sweeney Todd, one character's name was changed a couple of times in news reports because it was a spoiler (if you've seen the movie or the show, you know what I mean). In this case, it could have to do with a flashback to another/dual role (Josette?)
Let's try to be objective here, the filming hasn't even started yet- there is plenty of time to learn all the details. Heck, just yesterday I was looking at the Rango listing on IMDb, and I saw that Johnny is playing Rango and "Lars". Who the heck is Lars?? And it's less than 2 weeks before the film is released, if "Lars" even turns out to be legit. Just trying to point out that it's not that unusual for not all the info to be immediately known.
All this said, of course, I can't wait to know the answer!