SNM:
Disagree. I think this should be an ongoing and open-ended world with stories that begin and end within it. Each author needs to let the other authors know what they're doing so that contradictions don't occur (and so that terrible ideas can be vetted), but I don't think we need any more organization than that. In theory, someone should be able to join the project a year from now and add another story to the Zark universe.
I'm happy with a very loose editing process and being very open-ended; however you slightly contradict yourself by saying that contradictions shouldn't occur and terrible ideas can be vetted (I presume you really mean refused). Therefore you are de facto proposing some kind of vetting process.
I must make clear that there must be no competitiveness and no prizes for the best story, and that must be made clear to commenters.
In my opinion there has to be a small starting committee, (a benign dictatorship) set up to agree and set the original parameters, and write or the first set of stories.
Of course the if LSF is to host this Flopsy and Februs would have to agree and hopefully Flopsy (time allowing)would participate.
I cannot imagine it being a success without properly defined parameters.
I'm very happy with the name Zark btw.