We will try not to import bookmarks of threads that you have already found again and bookmarked. Since you now have the ability to bookmark individual posts, there might be a few extra bookmarks for posts within the same thread if your bookmark isn’t for exactly the same post.
I had written about this before within a thread, but I pulled that information out into a new one.
This should take you back to your original location. We’ll look into why it might not be working.
This is exactly right. Sometimes we need to reprioritize on the fly to handle more critical issues. We also thought twice about releasing something big right before the holiday. 
(we learned!) We anticipate Private Messages to be available this week, but it depends on how the import process goes. Even after they are imported I’m sure there will be some cleanup work to be done.