Hi there. First off, what verison of Poser are you using? The most recent verisons (10, PP2014, 11, and PP11) all have built in Pixar Subdivision tech. You just have to change the skinning method in the figure drop down menu. As far as I know, there is no way to subdivide the figure in Zbrush, reimport it and keep the fuctionality of the figure with out re rigging it. The morphs will not work either. Poser native subdivision, if you have a newer release of the software, is basically your go to.