I don’t know that you need all of those versions, and am a little concerned that there may be problems connected with having them all on board, but then again I don’t know that for a fact. My motto is always simple is best, so I have only Version 4.5.1.56 Pro Edition, and would think that is all that’s needed.

The reason you need DS is to provide a target for the Install Manager, at this point any way. DAZ sets up the DAZ 3D Studio My library with a Runtime of its own, and Poser sets up Poser Pro 2012 Content with its own Runtime, and a Downloads file location for future Poser Runtimes you will add.
The Install Manager sets up a My DAZ 3D Library with its own Runtime plus other stuff, which is not to be confused with DAZ 3D Studio My library (above). Now this at first sounds a bit crazy, as you now have four libraries, each with their own Runtimes, but from this you can gain a very easily understood organization that will save you a lot of hair pulling in the future, once you understand it.
The first library (DAZ 3D Studio My library) is only for files that came with DS originally.
The second library (Poser Pro 2012 Content) is only for files that came with Poser originally.

These should never be added to, to preserve the integrity of the two programs.

The Install Manager will load all of your additional DAZ files to the My DAZ 3D Library second DAZ library, all done neat and proper.
And last but not least, you will be placing all of your additional Poser files in Poser Pro 2012 Content “Downloads”, never the Poser Pro 2012 Content “Runtime” file location where all of your Poser original files are. This way if you mess-up, you don’t destroy the basic operation of the Poser program, which I have done several times.

Once both programs are configured properly, they will display all four library locations and any files in them that they can use respectively. From here on out you may be temporarily confused, but ultimately hopefully never again lost  ;) 

I will watch for your questions daily. Good Luck!