You can remove the morphs from Victoria 3 characters within Poser itself, using the REM poses, or delete them from the character files with Mason's Morph Manager utility (available in Free Stuff).

Do you have file compression enabled in Poser? The files are text-based, so they compress extremely well (sometimes as little as 15% of the original size). The downside is that Morph Manager and many other utilities can't read compressed files directly.