Artists, Go-Z and inflation deformer are your friends here.  Its an unfortuate situation but necessary because Poser is a artist grade toolset and "Pro Figures" are anatomically accurate so children and child textures would be avoided by most content creators because of the possibility that thier IP may be associated with bad intent.  So DIY is the best route for artist that way the creator controls the renders.  Its too hot a third rail for the most of the artist grade content developers.