I was hoping I could pick your guys' brains.

As a writer, how dangerous is it for me to be running approximately 8 different plots at the same time? Does anyone know any creative writing resources that deal with multiple coinciding storylines? I am early enough into my Eberron campaign project that I could absolutely pull back on some, or even all, of the convolutions for simplicity's sake, but I am somewhat constrained by a time limit of about a week.
In a nutshell, I'm looking at:
>the storyline for the [McGuffin] (1)
>character arcs for each of my four players (4)
>two players sharing the same faction of Dragonmarked house (1)
>the other two belong to separate but similar military units in service of the same country, presumably under the same overarching chain of command (2?)
>the plot [of the Enemy] (1)
>the plot(s) of [the other Dragonmarked houses] (2-11)

So far, I've written about a paragraph at minimum for everything, essentially establishing their relevancy to the PCs and/or their factions. I intend to leave it here for now, and remain narratively flexible, following my players' actions, but my concern lies in both the near and distant future. There's also the sheer customizability of the setting; as the campaign progresses, I'm going to need to start weaning off of the established lore and start building increasingly more and more of my own. How does one even began to organize and manage all of that?