I already have X3e producer with all the bells and whistles, I chose the install all option for platinum just in case.
It's probably going to reinstall stuff I already have.
Am I safe not bothering with AD2, DimPro, Rapture, Melodyne, etc? Anything new there?
Are there any recommendations for getting the new stuff without disrupting the old stuff?

Yes, just install Platinum, the help file and the Anderton FX Collection.
That would bring you up to date.