There have been agreements and disagreements about the actual workflow concerning DAZ3D's Generation 4 installation and where it should finally reside.  I tend to agree, they could be placed in any runtime an individual desires, as long as model and morph++ package occupy the same folder for correct deltas referencing.  The .cr2's do contain relative pathways, however, if you have spawned scenes under the old convention, generating  absolute pathways, and, afterwards, upgrade and move content, those pathways within the pz2's will be broken. 

You should not encounter too many problems if you link your P6 runtime to P7.  My advice, if you are adament about moving content, note an exact inventory of the content in question, copy the content over, then double-check that everything is in working order before deleting the old. 
And markschum is correct, there is a list located on the DAZ html readme located within the Poser folder.