Yes, with a VPS you can install whatever you want on it, much like your own desktop computer. Install WordPress, or Drupal, or Ghost, or whatever you want. As long as the VPS resources are enough to handle all of them running at once
I've created a forum to replace an old phpbb forum. Many of the old users want me to import old posts/thread to the new one. So, I want suggestions how I can do that. Perhaps manually if it's a good solution.