Victoria 4 does not really work in P4.  I tried to beta test some products for her in P4 way back in the early days of the figure's release.  All the magnets caused issues.  I also found problems with the ExP morphs.  Genesis, Generation 5 figures or higher from DAZ will not work in anything lower than P9.  They are weight mapped and require the DSON importer which is a Python script to get them into Poser.  Straight Poser4 does not have Python scripting.  Python scripting was not introduced in Poser ProPack along with the set room.

Poser 8 figures and Miki3 will not work in Poser 4 because the have the spherical joint fall off rigging introduced in P8.