PZ2's are pose files. They can be edited in any text editor or you can adjust the pose in Poser and resave it, thereby effectively "editing" the file. RSR files are P4 thumbnail files for the various library items. They can also be accompanying files to obj meshes. Also, I believe there's one big one in Poser's main directory (I don't know what it's for). In any case, I don't think you can--or should--edit these. But I could be wrong.